Practice Test


Q1) Wavelength of the wave is the distance between two particles of the medium having a phase difference of : Show Answer


Q2) Longitudinal waves cannot be propagated through: Show Answer


Q3) The velocity of sound is measured in hydrogen and oxygen at a certain temp. The ratio of the velocities is: Show Answer


Q4) Sound travels in rocks are in the form of: Show Answer


Q5) The longitudinal and transverse waves can be distinguished by studying the property of: Show Answer


Q6) When a wave is reflected from a rigid surface, it undergoes a phase change given by: Show Answer


Q7) The intensities of sound are in the ratio 1 : 16 for two waves of same frequency and travelling in same medium. Their amplitudes are in the ratio: Show Answer


Q8) The sound generator dipped in sea is sending waves of wavelength 2.5 m and frequency 580 Hz. The velocity of sound in sea water is: Show Answer


Q9) Transverse waves are generated in two steel wires A and B with a source of 512 Hz. If their diameters are in the ratio 2 : 1 and tensions in the ratio 2 : 1, the velocities of the waves are in the ratio: Show Answer


Q10) An observer at sea coast sees 54 waves striking a rock per minute. If wavelength is 10 m, what is the velocity of wave? Show Answer


Q11) The velocity of sound in air increased as the temperature increases. This increase in velocity is: Show Answer


Q12) The essential properties of a medium for the propagation of mechanical waves are: Show Answer


Q13) The amplitude of sound waves corresponding to normal conversation of human beings is of the order of: Show Answer


Q14) Under similar conditions of temperature and pressure, in which of the following gases will the velocity of sound be least? Show Answer


Q15) A string when stretched with a weight of 9 kg weight produces a note of frequency 256. Calculate the weight to produce an octave of the note: Show Answer


Q16) Stationary waves of frequency 200 are formed in air. If velocity of the wave is 360 m/s the shortest distance between anti-nodes will be: Show Answer


Q17) When a tuning fork beings to vibrate, the vibrations of its two prongs: Show Answer


Q18) When stationary waves are set up, which of the following statements is applicable? Show Answer


Q19) Two sources of intensities ratio 25 : 1 interfere. The ratio of intensities at maxima and minima will be: Show Answer


Q20) In the production of beats by the two waves of same amplitudes and nearly same frequencies, the maximum loudness heard corresponding to each of the constituent wave is: Show Answer


Q21) A fork gives 5 beats with a 40 cm length of sonometer wire. If the length of the wire is shortened by 1 cm, the number of beats is still the same. The frequency of the fork is: Show Answer


Q22) A certain string will resonate to several frequencies, the lowest of which is 200 Hz. What are the next three higher frequencies to which it resonates? Show Answer


Q23) A string of 0.3 m length is found to resonate in 3 segments (nodes at both ends) when the driving frequency is 20 Hz. The speed of the wave in the spring is: Show Answer


Q24) The string of violin has a frequency of 440 Hz. If the violinist shortens the string by one-fifth, by fingering it, its frequency will be changed by: Show Answer


Q25) A wire of sonometer is 1 m in length and has a fundamental frequency of 330 Hz. The velocity of transverse waves along the wire is: Show Answer


Q26) Two wires A and B and stretched between two points. The diameter, tension and density of B are twice that of A. The ratio of frequency B to that of A is: Show Answer


Q27) A fork when sounded with a fork of 256 produces 2 beats per sec. On loading the second fork with wax, the number of beats fall to one per sec. The frequency of the first fork is: Show Answer


Q28) A wire under tension vibrates with a frequency of 450 Hz. What would be the fundamental frequency if the wire were half as long, twice as thick and under one-fourth tension: Show Answer


Q29) If the frequency of the vibration of a string is increased by a factor of two, then the tension in the string should be: Show Answer


Q30) A closed end organ pipe has a frequency of 100 Hz as its fundamental note. The frequency of third harmonic will be: Show Answer


Q31) An open end organ pipe of fundamental frequency 550 Hz is filled with hydrogen, its frequency will: Show Answer


Q32) In resonance tube two position of resonance are obtained at 15 cm and 48 cm. If the frequency of the fork is 500 Hz, the velocity of sound is: Show Answer


Q33) A closed pipe of 10 cm length has its fundamental, half that of the second overtone of an open end pipe, find the length of the pipe: Show Answer


Q34) A tube of glass open at both ends, has a fundamental frequency in air, the tube is dipped vertically in water so that half of it is in water. The frequency of air column is: Show Answer


Q35) If the source moves away with such a velocity from listener, who is at rest that frequency of the note is halved, then its velocity is (velocity of sound = 332 m/s): Show Answer


Q36) The frequency of a source is received by an observer is 10% low. The velocity of the observer with respect to source is (velocity of sound = 350 m/s): Show Answer


Q37) The intensity of sound gets reduced by 20% on passing through a wall. The reduction of intensity on passing through two consecutive similar walls will be: Show Answer


Q38) A source of sound that is emitting a frequency of 450 cycles/second is approaching a stationary observer with a speed of 34 metres/second. If the speed of sound in air is 340 metres/second the apparent frequency heard by the observer is: Show Answer


Q39) A motor cyclist moving with 30 km/hr blows a whistle of 476 Hz towards a cliff. If velocity of sound is 1220 km/hr, the apparent frequency of the echo heard by him is: Show Answer


Q40) An engine standing at the platform blows a whistle of frequency 305 vib/sec. If the velocity of sound be 1220 km/hr, the frequency of the whistle as heard by a man running towards the engine with a speed of 20 km/hr is: Show Answer


Q41) The wavelength of light coming from a star shifts towards the violet end of the spectrum.
This shows that the star is: Show Answer


Q42) Ultrasonics are used for stirring liquid solutions in order to produce: Show Answer


Q43) The wall of hall for a cinema shows should: Show Answer


Q44) The speed of longitudinal wave in a thin brass rod is 3480 metre/second. If the rod clamped at one end gives a fundamental frequency of 435 cycles/second, the length of the rod is: Show Answer


Q45) A wave of frequency 100 Hz travels along a string towards its fixed end. When this wave travels back, after reflection, a node is formed at a distance 10 cm from the fixed end. The speed of the wave (reflected and incident) is: Show Answer


Q46) For a certain organ pipe three successive harmonics are 425, 595 and 765 Hz. What is the fundamental frequency? Show Answer


Q47) On producing waves of frequency 1000 Hz in a gas filled kundt's tube, the total distance between 6 successive nodes is 82.5 cm. Find the speed of sound in the gas? Show Answer


Q48) A uniform rope of mass 0.1 kg and length 2.45 m hangs from the ceiling. Find the speed of transverse waves at a point 0.5 m distant from the lower end. Show Answer


Q49) A uniform rope of mass 0.1 kg and length 2.45 m hangs from the ceiling. Find the speed of transverse waves at a point 0.5 m distant from the lower end.calculate the time taken by the wave to travel full length of the rope: Show Answer


Q50) Standing waves are produced in 10 m long stretched string. If the string vibrates in 5 segments and the wave velocity is 20 m/s, the frequency is: Show Answer


Q51) An observer is watching two vehicles of same velocity (4 m/s). The former is approaching towards the observer while the later receding. If the frequency of the siren of the vehicle is 240 Hz and velocity of sound in air is 320 m/s, then the beats produced is: Show Answer


Q52) Resonance is a special case of: Show Answer


Q53) Which waves are used in sonography? Show Answer


Q54) If the temperature increases, then what happens to the frequency of the sound produced by the organ pipe? Show Answer


Q55) If a wave enters from air to water, then what remains unchanged? Show Answer


Q56) A string oscillating at fundamental frequency under a tension of 225 N produces 6 beats per second with a sonometer. If the tension is 256 N, then again oscillating at fundamental note is produces 6 beats per second with the same sonometer. What is the frequency of the sonometer? Show Answer


Q57) The length of a sonometer wire AB is 110cm. Where should the two bridges be placed from A to divide the wire in 3 segments whose fundamental frequencies are in the ratio of 1 : 2 : 3? Show Answer


Q58) A weight is attached to the free end of a sonometer wire. It gives resonance at a length of 40 cm when it is resonanced with a tuning fork of frequency 512. The weight is then immersed wholly in water, the resonant length is reduced to 30 cm. The relative density of the fluid in which weight suspended is: Show Answer


Q59) Two open organ pipes of length 50 cm and 50.5 cm produce 0.3 beats/sec. Then the velocity of sound is: Show Answer


Q60) In stationary wave the strain is: Show Answer


Q61) A wave of frequency 100 Hz is sent along a string towards of fixed end. When this wave travels back after reflection, a node is formed at a distance of 10 cm from the fixed end of the string. The speed of incident (and reflected) wave are: Show Answer


Q62) A glass tube of 1.0 m length is filled with water. The water can be drained out slowly at the bottom of the tube. If a vibrating tuning fork of frequency 500 c/s is brought at the upper end of the tube and the velocity of sound is 330 m/s, then the total number of resonances obtained will be: Show Answer


Q63) A long glass tube is held vertically in water. A tuning fork is struck and held over the tube. Strong resonances are observed at two successive lengths 0.50 m and 0.84 m above the surface of water. If the velocity of sound is 340 m/s then the frequency of the tuning fork is: Show Answer


Q64) A source of sound S is moving with a velocity 50 m/s towards a stationary observer. The observer measures the frequency of the source as 1000 Hz. What will be the apparent frequency of the source when it is moving away from the observer after crossing him? The velocity of sound in the medium is 350 m/s. Show Answer


Q65) If the intensity of sound is doubled, the sound level will increase by nearly: Show Answer


Q66) A jet plane travels at Mach 2 at an altitude of 1600 m. How far past an observer will the plane be when the shock wave hits him? Show Answer


Q67) The intensity level due to two waves of the same frequency in a given medium are 1 bel and 5 bel. Then the ratio of amplitudes is: Show Answer


Q68) Two trains A and B approach a stationary observer from opposite sides with speeds 15 m/s and 30 m/s respectively. Observer hears no beats. If frequency of whistle of train B is 504 Hz, the frequency of whistle of A is (speed of sound = 330 ms): Show Answer


Q69) A radio wave of frequency 840 MHz is sent towards an aeroplane. The frequency of radio echo has a frequency 2.8 kHz more than the original frequency. Then the velocity of the aeroplane is: Show Answer


Q70) The number of waves contained in a unit length of the medium is called: Show Answer


Q71) Two waves 50 cm and 51 cm is wavelengths produce 12 beats/sec. The velocity of sound is: Show Answer


Q72) In a wave the time required for a particular point to move from max. displacement to zero displacement is 0.170 second. The frequency of the wave is: Show Answer


Q73) A toothed wheel is rotated at 120 r.p.m. and a postcard is placed against the teeth. How many teeth (frequency) must the wheel have to produce a note whose pitch is same as that of a tuning fork of frequency 256/second? Show Answer


Q74) Mechanical waves on the surface of a liquid are: Show Answer


Q75) In the open organ pipe the fundamental frequency is 30 vibrations/second. If the organ pipe is closed, then the fundamental frequency will be: Show Answer


Q76) Two whistles A and B produces notes of frequencies 660 Hz and 596 Hz respectively. There is a listener at the middle point of the line joining them. Both the whistles B and the listener start moving with speed 30 m/s away from the whistle A. If speed of sound be 330 m/s, how many beats will be heard by the listener? Show Answer


Q77) Two sirens situated one kilometre apart are producing sound of frequency 330 Hz. An observer starts moving from one siren to the other with a speed of 2 m/s. If the speed of sound be 330 m/s, what will be the beat frequency heard by the observer? Show Answer


Q78) An observer is watching two vehicles of same velocity (4m/s). The former is approaching towards the observer while the later receding. If the frequency of the siren of the vehicle is 240 Hz and velocity of sound in air is 320 m/s, then the beats produced is: Show Answer


Q79) Which one is not produced by sound waves in air? Show Answer


Q80) A pulse or a wavetrain travels along a stretched string and reaches the fixed end of the string. It will be reflected back with: Show Answer


Q81) What is frequency of radio waves transmitted by a station, if the wavelength of these waves is 300 m? Show Answer


Q82) The combination of two or more notes which produces a melodious effect on ear is called: Show Answer


Q83) Energy is not carried by: Show Answer


Q84) Which of the following emits sound of highest pitch? Show Answer


Q85) In a sinusoidal wave, the time required for a particular point to move from maximum displacement to zero displacement is 0.170 s. The frequency of the wave is: Show Answer


Q86) Two trains, one coming towards and another going away form an observer both at 4 m/s, blow whistles simultaneously giving sounds of frequency 300 Hz. Find the number of beats produced. Show Answer


Q87) The apparent frequency of a note, when a listener moves towards a stationary source, with velocity of 40 m/s, is 200 Hz. When he moves away from the same source with the same speed, the apparent frequency of the same note is 60 Hz. The velocity of sound in air is (in m/s) is: Show Answer


Q88) The velocity of sound is greatest in: Show Answer


Q89) The Doppler's effect is applicable for: Show Answer


Q90) A sonometer wire stretched with 64 newton is vibrating in its fundamental tone and in resonance with a vibrating tuning fork. Length of the vibrated part of sonometer wire is 10 cm and the mass is 1 gram. Vibrating tuning fork is brought far away from vibrated wire with a constant speed and an observer standing near the sonometer hears 1 beat per second. If the speed of sound in the air is 300 m/s then speed of tuning fork will be: Show Answer


Q91) 26 tuning forks are placed in a series such that each tuning fork produces 4 beats with its previous tuning fork. If the frequency of last tuning fork be three times the frequency of first tuning fork, then frequency of first tuning fork will be: Show Answer


Q92) A stretched wire, 60 cm long is vibrating with its fundamental frequency 256 Hz. If the length of the wire is decreased to 15 cm, and the tension remains the same, then the fundamental frequency of the vibration of the wire will be: Show Answer


Q93) 16 tuning forks are arranged in increasing order of frequency. Any two consecutive tuning forks when sounded together produce 8 beats per second. If the frequency of the last tuning fork is twice that of the first, the frequency of the first tuning fork is Show Answer


Q94) The velocity of sound in air depends upon: Show Answer


Q95) A tuning fork produces 4 beats/sec. with another fork of frequency 288 cps. A little wax is placed on the unknown fork and it then produces 2 beats/sec. The unknown frequency is: Show Answer


Q96) A tuning fork of known frequency 256 Hz makes 5 beats per second with the vibrating string of a piano. The beat frequency decreases to 2 beats/sec when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was: Show Answer


Q97) An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency? Show Answer


Q98) When two tuning forks (fork 1 and fork 2) are sounded simultaneously, 4 beats per second are heard. Now, some tape is attached on the prong of the fork 2. When the tuning forks are sounded again, 6 beats per second are heard. If the frequency of fork 1 is 200 Hz, then what was the original frequency of fork 2? Show Answer


Q99) A string is stretched between fixed points separated by 75 cm. It is observed to have a resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. Then the lowest resonant frequency for this string is: Show Answer


Q100) If the pressure amplitude in a sound wave is tripled, then the intensity of sound is increased by a factor of: Show Answer


Q101) Standing waves are produced in a 10 m long stretched string. If the string vibrates in 5 segments and the wave velocity is 20 m/s, the frequency is: Show Answer


Q102) The fact that light of transverse wave derives its evidence by the support from the observation that: Show Answer


Q103) In a transverse progressive wave of amplitude A, the maximum particle velocity is four times its wave velocity, then the wavelength of the wave is: Show Answer


Q104) A source and an observer move away from each other, with a velocity of 10 m/s with respect to ground. If the observer finds the frequency of sound coming from the source as 1950 Hz. Then actual frequency of the source is (velocity of sound in air = 340 m/s): Show Answer


Q105) A resonance air column of length 20 cm resonates with a tuning fork of frequency 250 Hz. The speed of sound in air is: Show Answer


Q106) Which of the following is not a transverse wave? Show Answer


Q107) A stone is dropped into a lake from a tower 500 metre high. The sound of the splash will be heard by the man approximately after: Show Answer


Q108) A tuning fork vibrates with two beats in 0.4 second, the frequency is: Show Answer


Q109) The tension in a piano wire is 10 N. What should be the tension in the wire to produce a note of double the frequency? Show Answer


Q110) A siren emitting sound of frequency 800 Hz is going away from a static listener with a speed of 30 m/s. The frequency of sound heard by listener is (velocity of sound = 300 m/s): Show Answer


Q111) A siren placed at a railway platform is emitting sound of frequency 5 kHz. A passenger sitting in a moving train A records a frequency of 5.5 kHz, while the train approaches the siren. During his return journey in a different train B, he records a frequency of 6.0 kHz, while approaching the same siren. The ratio of velocity of train B to the velocity of train A is: Show Answer


Q112) A sonometer wire resonants with a given tuning fork forming standing waves with five antinodes between the two bridges when a mass of 9 kg is suspended from the wire. When this mass is replaced by mass M, the wire resonates with the same tuning fork forming three antinodes for the same position of bridges. The value of M is: Show Answer


Q113) A string in a musical instrument is 50 cm long and its fundamental frequency is 800 Hz. If a frequency of 1000 Hz is to be produced, then required length of string is: Show Answer


Q114) In a stationary waves are variation in pressure at nodes is: Show Answer


Q115) A police car moving at 22 m/s chases a motor cyclist. The policeman sounds his horn at 176 Hz, while both of then move towards a stationary siren of frequency 165 Hz. Calculate the speed of motor cycle if it is given that he does not observe any beats. Show Answer


Q116) In the experiment for the determination of speed of sound in air using the resonance column method, the length of the air column that resonates in the fundamental mode, with a tuning fork is 0.1 m. When this length is changed to 0.35 m, the same tuning fork resonates with the first overtone. Calculate the end correction: Show Answer


Q117) Wall of auditorium should be: Show Answer


Q118) Quality of sound depends upon: Show Answer


Q119) If two tuning forks A and B are sounded together, they produce 4 beats per second. A is then slightly loaded with wax, they produce less beats when sounded again. The frequency of A is 256 Hz. The frequency of B will be: Show Answer


Q120) A stone is hung in air form a wire which is stretched over a sonometer. The bridges of the sonometer are 40 cm apart when the wire is in unison with a tuning fork of frequency 256. When the stone is completely immersed in water, the length between the bridges is 22 cm for re-establishing unison. The specific gravity of the material of the stone is: Show Answer


Q121) The intensity of a sound wave while passing through an elastic medium falls down to 10% as it covers one metre distance through the medium. If the initial intensity of the sound wave was 100 decibels, its value after it has passed through 3 metre thickness of the medium will be: Show Answer


Q122) Apparatus used to find out velocity of sound in gas is: Show Answer


Q123) If fundamental frequency of closed pipe is 50 Hz, then frequency of second overtone is: Show Answer


Q124) A source of frequency 150 Hz is moving in the direction of a person with a velocity of 110 m/s. The frequency heard by the person will be (speed of sound in medium = 330 m/s): Show Answer


Q125) The waves produced by a motorboat, sailing in water, are: Show Answer


Q126) An organ pipe enclosed at one end has fundamental frequency of 1500 Hz. The maximum number of overtones generated by this pipe which a normal person can hear is: Show Answer


Q127) Which of the following emit a pure sine wave? Show Answer


Q128) When tuning fork is vibrating the vibrations of two tuning prongs: Show Answer


Q129) A source of sound of frequency 600 Hz is placed inside water. The speed of sound in water is 1500 m/s, and in air, it is 300 m/s. The frequency of sound recorded by an observer who is standing in air is: Show Answer


Q130) A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Q are at distances of 2 m and 3 m respectively from the source. The ratio of the intensities of the waves at P and Q is: Show Answer


Q131) A tuning fork of 512 Hz is used to produce resonance in a resonance tube experiment. The level of water at first resonance is 30.7 cm and at second resonance is 63.2 cm. The error in calculating velocity of sound is: Show Answer


Q132) Two tuning forks have frequencies 450 Hz and 454 Hz respectively. On sounding these forks together, the time integral between successive maximum intensities will be: Show Answer


Q133) A source of sound S is moving with a velocity 50 m/s towards a stationary observer. The observer measures the frequency of the source as 1000 Hz. What will be the apparent frequency of the source when it is moving away from the observer after crossing him? The velocity of sound in the medium is 350 m/s.
Show Answer


Q134) Twenty six tuning forks are arranged in order of decreasing frequencies. Each fork gives 3 beats with the adjoining fork. Given that first is octave of the last then the frequency of 18th fork is: Show Answer


Q135) A boat at anchor is rocked by waves whose crests are 100 m apart and velocity is 25 m/s. The boat bounces up once in every: Show Answer


Q136) Two points are located at a distance of 10 m and 15 m from the source of oscillation. The period of oscillation is 0.05 sec.and velocity of wave is 300 m/sec. What is phase difference between the oscillations of two points? Show Answer


Q137) The driver of a car travelling with speed 30 m/sec towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by driver is: Show Answer


Q138) Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force. Mass per unit length of both the strings is same and equal to 1 g/m. When both the strings vibrate simultaneously the number of beats is: Show Answer


Q139) A tuning fork of frequency 512 Hz makes 4 beats per second with the vibrating string of a piano. The beat frequency decreases to 2 beats per sec when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was: Show Answer


Q140) Sound waves travel at 350 m/s through a warm air and at 3500 m/s through brass. The wavelength of a 700 Hz acoustic wave as it enters brass from warm air. Show Answer


Q141) A whistle is whirled in a circle of radius one metre and traverses the circular path twice per second. An observer is situated outside the circle but in its plane. If the velocity of sound is 332 m/s, then the interval between the highest and the lowest observed pitch is: Show Answer


Q142) An increase in intensity level of one decibel implies an increase in intensity of Show Answer


Q143) A source of sound is moving with a constant speed of 20 m/s emitting a note of a fixed frequency. The ratio of the frequencies observed by a stationary observer when the source is approaching him and after it has crossed him is: Show Answer


Q144) The difference between the apparent frequencies of a source of sound as perceived by a stationary observer during its approach and recession is 2% of the actual frequency of the source. If the speed of sound is 300 m/s, the speed of the source is: Show Answer


Q145) The frequency of a radar is 780 MHz. When it is reflected from an approaching aeroplane, the apparent frequency is more than the actual frequency by 2.6 kHz. The speed of the aeroplane is: Show Answer


Q146) A sample of oxygen at N.T.P. has volume V and a sample hydrogen at N.T.P. has volume 4V. Both the gases are mixed and the mixture is maintained at N.T.P. If the speed of sound in hydrogen at N.T.P. is 1270 m/s, that in the mixture will be: Show Answer


Q147) A set of 36 tuning forks is arranged in series of decreasing frequencies. Each fork gives 3 beats with succeeding one. The first fork is an octave of the last. The frequency of the 15th tuning fork from start is: Show Answer


Q148) When the prong of tuning fork is struck against some object, both the prongs vibrate: Show Answer


Q149) A stretched wire of length 110 cm is divided into three segments whose frequencies are in ratio 1 : 2 : 3. Their lengths must be: Show Answer


Q150) A tuning fork A of frequency 512 Hz produces 4 beats per second when sounded with a tuning fork B. Due to filing of the prongs of the tuning fork B, the number of beats per second becomes 6. The actual frequency of B is: Show Answer


Q151) Two sound waves of length 1 m and 1.01 m in a gas produce 10 beats is 3 s. The velocity of sound in gas is: Show Answer


Q152) The fundamental frequency of a closed organ pipe is equal to second overtone of an open organ pipe. If the length of closed organ pipe is 15 cm, the length of open organ pipe is: Show Answer


Q153) When stationary waves are set up: Show Answer


Q154) A uniform rope of length 12 metres and mass 6 kg hangs vertically from a rigid support. A block of mass 2 kg is attached to the free end. A transverse pulse of wavelength 0.06 metre is produced at the lower end of the rope. What is the wavelength of the pulse when it reaches the top of the rope? Show Answer


Q155) Two parts of sonometer wire divided by a moveable bridge differ in length by 0.2 cm and produce 1 beat per second, when sounded together. The total length of wire is 1 m, then the frequencies are: Show Answer


Q156) The power of sound from the speaker of a radio is 20 milliwatt. By turning the knot of the volume control the power of the sound is increased to 400 milliwatt. The power increase in decibels as compared to original power is: Show Answer


Q157) The propagation constant or angular wave number is Show Answer


Q158) A string of mass 2.5 kg is under a tension of 200 N. The length of the stretched string is 20 m. If a transverse jerk is struck at one end of the string, how long does the disturbance take to reach the other end? Show Answer


Q159) A meter-long tube open at one end with a moveable piston at the other end, shows resonance with a fixed frequency source (a turning fork of frequency 340 Hz) when the tube length is 25.5 cm or 79.3 cm. Estimate the speed of sound in air at the temperature of the experiment. Show Answer


Q160) A bat is flitting about in a cave navigating via ultrasonic beeps. Assume that the sound emission frequency of the bat is 40 kHz. During one fast swoop directly toward a flat wall surface, the bat is moving at 0.03 times the speed of sound in air. The frequency the bat hears reflected off the wall is Show Answer


Q161) Then n = ? Show Answer


Q162) What harmonic will the resonance be observed if one end of the pipe is closed? Show Answer


Q163) Calculate the frequency of the sound as detected by the target. Show Answer


Q164) Some of the sound reaching the target gets reflected back to the rocket as an echo. Calculate the frequency of the echo as detected by the rocket. Show Answer


Q165) In a mechanical longitudinal wave, the particles of the medium Show Answer


Q166) Which of the following changes at an anti-node in a stationary wave? Show Answer


Q167) Shock waves are produced by objects Show Answer


Q168) A tuning fork P of frequency 512 Hz produces 6 beats per second with another tuning fork Q. When Q is slightly filled, the number of beats heard per second is 8. The original frequency of Q is Show Answer


Q169) The ratio of intensities of sounds A and B is 100 : 1. Then the intensity level of A is greater than that of B Show Answer


Q170) In the sonometer experiment, a tuning fork of frequency 256 Hz is in resonance with 0.4 m length of the wire when the iron load attached to free end of wire is 2 kg. If the load is immersed in water, the length of the wire in resonance would be : (specific gravity of iron = 8) Show Answer


Q171) If the speed of a transverse wave on a stretched string of length 1 m is 60 m/s, what is the fundamental frequency of vibration? Show Answer


Q172) Two tuning forks of frequencies 256 Hz and 258 Hz are sounded together. The time interval between consecutive maxima heard by the observer is Show Answer


Q173) The fundamental frequency of a string stretched with a weight of 4 kg is 256 Hz. The weight required to produce its octave is Show Answer


Q174) A source X of unknown frequency produces 8 beats per second with a source of 250 Hz and 12 beats per second with a source of 270 Hz. The frequency of the source X is Show Answer


Q175) Statement 1 : When pressure in a gas changes velocity of sound in gas may change.
Statement 2 : Velocity of sound is directly proportional to square root of pressure. Show Answer


Q176) Statement 1 : If wave enters from one medium to another medium then sum of amplitudes of reflected wave and transmitted wave is equal to the amplitude of incident wave.
Statement 2 : If wave enters from one medium to another medium some part of energy is transmitted and rest of the energy is reflected back. Show Answer


Q177) Wave speed of louder wave is : Show Answer


Q178) When the given waves superpose, the number of times the intensity of sound becomes maximum in 1 second is : Show Answer


Q179) An empty vessel is partially filled with water. The frequency of vibration of air volume in the vessel Show Answer


Q180) What is the effect of increase in temperature on the frequency of sound produced by an organ pipe? Show Answer


Q181) Which of the following is a mechanical wave? Show Answer


Q182) When a wave passes from one medium to another, there is change in Show Answer


Q183) It is possible to distinguish between transverse and longitudinal waves by studying the property of Show Answer


Q184) A sonometer wire supports a 4 kg load and vibrates in fundamental mode with a tuning fork of frequency 416 Hz. The length of the wire between the bridges is now doubled. In order to maintain fundamental mode, the load should be changed to Show Answer


Q185) The intensity level of sound wave is said to be 4 decibel. If the intensity of wave is doubled, then the intensity level of sound as expressed in decibel would be Show Answer


Q186) Two wires are kept tight between the same pair of supposts. The tensions in the wires are in the ratio 2 : 1, the radii are in the ratio 3 : 1 and the densities are in the ratio 1 : 2. The ratio of their fundamental frequencies is Show Answer


Q187) A toothed wheel is rotating at 240 rpm and a post card is held against the teeth. If the pitch of the tone is 256 Hz, then the number of teeth on the rotating wheel is Show Answer


Q188) A string divided into three segments, so that the segments possess fundamental frequencies in the ratio 1 : 2 : 3. Then, the lengths of the segments are in the ratio Show Answer


Q189) Statement 1 : When a sound source moves towards observer, then frequency of sound increases.
Statement 2 : Wavelength of sound in medium towards observer is decreased. Show Answer


Q190) Statement 1 : Newton's equation for speed of sound was found wrong because, he assumed the process as isothermal.
Statement 2 : When sound propagates the compressions and rarefactions happens so rapidly that there is not enough time for heat to be distributed. Show Answer


Q191) The amplitude of each component wave is Show Answer


Q192) The separation between two consecutive nodes is Show Answer


Q193) The end point x = 0 is Show Answer


Q194) A stone is hung in air from a wire which is stretched over a sonometer. The bridges of the sonometer are L cm apart when the wire is in unison with a tuning fork of frequency N. When the stone is completely immersed in water, the length between the bridges is l cm for re-establishing unison, the specific gravity of the material of the stone is Show Answer


Q195) The disc of a siren containing 60 holes rotates at a constant speed of 360 rpm. The emitted sound is in unison with a tuning fork of frequency Show Answer


Q196) Quality of a musical note depends on Show Answer


Q197) A 5.5 m length of string has a mass of 0.035 kg. If the tension in the string is 77 N, the speed of a wave on the string is Show Answer


Q198) A tuning fork of frequency 200 Hz is in unison with a sonometer wire. The number of beats heard per second when the tension is increased by 1% is Show Answer


Q199) An observer moves towards a stationary source of sound with a velocity one-fifth of the velocity of sound. What is the percentage increases in the apparent frequency? Show Answer


Q200) A tuning fork of frequency 392 Hz, resonates with 50 cm length of a string under tension (T). If length of the string is decreased by 2%, keeping the tension constant, the number of beats heard when the string and the tuning fork made to vibrate simultaneously is Show Answer


Q201) If in a resonance tube a oil of density higher than that water is used then at the resonance frequency would Show Answer


Q202) Three sources of equal intensities with frequencies 400, 401 and 402 vib/s are sounded together. The number of beats/s is Show Answer


Q203) A cylindrical tube containing air is open at both ends. If the shortest length of the tube for resonance with a given fork is 2 cm, the next shortest length for resonance with the same fork will be Show Answer


Q204) On which principle does sonometer works? Show Answer


Q205) The intensity ratio of two waves is 1:9. The ratio of their amplitudes, is Show Answer


Q206) The driver of a car travelling with speed 30 metres per second towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 metres per second, the frequency of the reflected sound as heard by the driver is Show Answer


Q207) The musical interval between two tones of frequencies 320 Hz and 240 Hz is Show Answer


Q208) Two tuning fork, A and B produce notes of frequencies 258 Hz and 262 Hz. An unknown note sounded with a produces certain beats. When the same note is sounded with B, the beat frequency gets doubled, the unknown frequency is Show Answer


Q209) The amplitude of two waves are in ratio 5:2. If all other conditions for the two waves. Are same, then what is the ratio of their energy densities?
Show Answer


Q210) The sound wave was produced in a gas is always Show Answer


Q211) Two waves of frequencies 20 Hz and 30 Hz. Travels out from a common point. The phase difference between them after 0.6 sec is Show Answer


Q212) The frequency of the fundamental note in a wire stretched under tension T is v. if the tension is increased to 25T, then the frequency of the fundamental note will be Show Answer


Q213) The waves in which the particles of the medium vibrate in a direction perpendicular to the direction of wave motion is known as Show Answer


Q214) The frequency of tuning forks A and B are respectively 3% more and 2% less than the frequency of tuning fork C. When A and B are simultaneously excited, 5 beats per second are produced. Then the frequency of the tuning fork 'A' in (in Hz) is Show Answer


Q215) In a stationary wave all the particles Show Answer


Q216) A standing wave having 3 nodes and 2 antinodes is formed between two atoms having a distance 1.21 Å between them. The wavelength of the standing wave is Show Answer


Q217) When both the listener and source are moving towards each other, then which of the following is true regarding frequency and wavelength of wave observed by the observer? Show Answer


Q218) The fundamental frequency of a sonameter wire is v. if its radius is doubled and its tension becomes half, the material of the wire remains same, the new fundamental frequency will be Show Answer


Q219) A pulse of a wave train travels along a stretched string and reaches the fixed end of the string. It will be reflected with Show Answer


Q220) If the temperature is raised by 1 K from 300 K the percentage change in the speed of sound in the gaseous mixture is (R = 8.31 J/mol-K) Show Answer


Q221) A sound absorber the sound level by 20 dB. The intensity decreases by a factor of Show Answer


Q222) The frequency of fundamental note in an organ pipe is 240 Hz. On blowing air, frequencies 720 Hz and 1200 Hz are heard. This indicates that organ pipe is Show Answer


Q223) Which of the following functions represent a wave? Show Answer


Q224) It is possible to distinguish between the transverse and longitudinal waves by studying the property of Show Answer


Q225) A wire under tension vibrates with a fundamental frequency of 600 Hz. If the length of the wire is doubled, the radius is halved and the wire is made to vibrate under one-ninth the tension. Then the fundamental frequency will become Show Answer


Q226) An underwater sonar source operating at a frequency of 60 kHz directs its beam towards the surface. If the velocity of sound in air is 330 m/s, the wavelength and frequency of waves in air are: Show Answer


Q227) A man sets his watch by the sound of a siren placed at a distance 1 km away. If the velocity of sound is 330 m/s Show Answer


Q228) When temperature increases, the frequency of a tuning fork Show Answer


Q229) When we hear a sound, we can identify its source from Show Answer


Q230) A string of 7 m length has a mass of 0.035 kg. If tension in the string is 60.5 N, then speed of a wave on the string is Show Answer


Q231) A string of length 2m is fixed at both ends. If this string vibrates in its fourth normal mode with a frequency of 500 Hz, then the waves would travel on it with a velocity of Show Answer


Q232) Velocity of sound in air
I. increases with temperature
II. Decreases with temperature
III. Increase with pressure
IV. Is independent of pressure
V. Is independent of temperature
Choose the correct answer
Show Answer


Q233) Two open organ pipes gives 4 beats/sec when sounded together in their fundamental nodes. If the length of the pipe are 100 cm and 102.5 cm respectively, then the velocity of sound is : Show Answer


Q234) At what speed should a source of sound move so that stationary observer finds the apparent frequency equal to half of the original frequency Show Answer


Q235) What is the base frequency if a pipe gives notes of frequencies 425, 255 and 595 and decide whether it is closed at one end or open at both ends Show Answer


Q236) A uniform rope having mass m hangs vertically from a rigid support. A transverse wave pulse is produced at the lower end. The speed (v) of wave pulse varies with height h from the lower end as shown in figure. Show Answer


Q237) When beats are produced by two progressive waves of the same amplitude and of nearly the same frequency, the ratio of maximum loudness to the loudness of one of the waves will be n. Where n is Show Answer


Q238) The frequency of a whistle of an engine is 600 cycles/sec is moving with the speed of 30 m/sec towards an observer. The apparent frequency will be (velocity of sound =330 m/s) Show Answer


Q239) The second overtone of an open pipe is in resonance with the first overtone of a closed pipe of length 2m. length of the open pipe is Show Answer


Q240) Find the fundamental frequency of a closed pipe, if the length of the air column is 42 m. (speed of sound in air =332 m/sec) Show Answer


Q241) Speed of sound at constant temperature depends on Show Answer


Q242) The angle between particle velocity and wave velocity in a transverse wave is Show Answer


Q243) A wave travelling in positive X-direction with A=0.2m has a velocity of 360 m/sec. If λ=60m, then correct expression for the wave is Show Answer


Q244) There are three of sources of sound of equal intensity with frequencies 400, 401 and 402 vib/sec. The number of beats heard per second is Show Answer


Q245) In Melde’s experiment, the string vibrates in 4 loops when a 50 g weight is placed in the pan of weight 15 g. To made the string vibrate in 6 loops, the weight that has to be removed from the pan in approximately Show Answer


Q246) The ratio of speed of sound in nitrogen and helium gas at 300 K is Show Answer


Q247) A device used for investigating the vibration of a fixed string of wire is Show Answer


Q248) Which of the following equations represents a wave? Show Answer


Q249) If the velocity of sound in air is 336 m/s. The maximum length of a closed pipe that would produce a just audible sound will be Show Answer


Q250) A whistle revolves in a circle with an angular speed of 20 rad/sec using a string of length 50 cm. If the frequency of sound from the whistle is 385 Hz, then what is the minimum frequency heard by an observer, which is far away from the centre in the same plane? (v=340 m/s) Show Answer


Q251) A source is moving towards an observer with a speed of 20 m/s and having frequency of 240 Hz. The observer is now moving towards the source with a speed of 20 m/s. Apparent frequency heard by observer, if velocity of sound is 340 m/s, is Show Answer


Q252) A tuning fork of frequency 340 Hz is vibrated just above the tube of 120 cm height. Water is poured slowly in the tube, what is the minimum height of water necessary for the resonance? Show Answer


Q253) What is the phase difference between two successive crests in the wave? Show Answer


Q254) Two waves having the intensities in the ratio of 9 : 1 produce interference. The ratio of maximum to the minimum intensity, is equal to Show Answer


Q255) Two identical plain wires have a fundamental frequency of 600 cycle per second when kept under the same tension. What fractional increase in the tension of one wires will lead to the occurrence of 6 beats per second when both wires vibrate simultaneously Show Answer


Q256) Two strings X and Y of a sitar produce a beat frequency 4Hz. When the tension of the string Y is slightly increased the beat frequency is found to be 2 Hz. If the frequency of X is 300 Hz, then the original frequency of Y was Show Answer


Q257) Learned Indian classical vocalists do not like the accompaniment of a harmonium because Show Answer


Q258) Two waves of wavelength 1.00m and 1.01m produces 10 beats in 3s. What is the velocity of the wave? Show Answer


Q259) Two waves are approaching each other with a velocity of 16 m/s and frequency n. The distance between two consecutive nodes is Show Answer


Q260) When two sound waves are superimposed, beats are produced when they have Show Answer


Q261) From a point source, if amplitude of waves at a distance r is A, its amplitude at a distance 2r will be Show Answer


Q262) A tuning fork vibrating with a sonometer having 20 cm wire produces 5 beats per second. The beat frequency does not change if the length of the wire is changed to 21 cm. The frequency of the tuning fork (in Hertz) must be Show Answer


Q263) Two sources produce sound waves of equal amplitudes and travelling along the same direction producing 18 beats in 3 seconds. If one source has a frequency of 341 Hz, the frequency of the other source may be Show Answer


Q264) When a sound wave goes from one medium to another, the quantity that remains unchanged is Show Answer


Q265) The wavelength of a wave is 990 cm and that of other is 100 cm. speed of sound is 396 m/s. The number of beats heard is Show Answer


Q266) Beats are produced when two progressive waves of frequency 256 Hz ad 260 Hz superpose. Then the resultant amplitude changes periodically with frequency of Show Answer


Q267) If T is the reverberation time of an auditorium of volume V then Show Answer


Q268) If vibrations of a string are to be increased by a factor of two, then tension in the string must be made Show Answer


Q269) A student determines the velocity of sound with the help of a closed organ pipe. If the observed length for fundamental frequency is 24.7 m, the length for third harmonic will be Show Answer


Q270) If sound wave travel from air to water, which of the following remain unchanged? Show Answer


Q271) A racing car moving towards a cliff sounds its horn. The drivers observe that the sound reflected from the cliff has a pitch one octave higher than the actual sound of the horn. If v = the velocity of sound, the velocity of the car is Show Answer


Q272) Two trains are moving towards each other with speeds of 20 m/s and 15 m/s relative to the ground. The first train sounds whistle of frequency 600 Hz, the frequency of the whistle heard by a passenger in the second train before the meets is (the speed of sound in air is 340 m/s) Show Answer


Q273) Two tuning forks A and B vibrating simultaneously produce 5 beats. Frequency of B is 512. It is seen that if one arm of A is filed, then the number of beats increases. Frequency of A will be Show Answer


Q274) In Melde’s experiment, the string vibrates in 4 loops when a 50g weight is placed in the pan of weight 15g. To make the string to vibrates in 6 loops the weight that has to be removed from the pan is Show Answer


Q275) If v is the speed of sound in air then the shortest length of the closed pipe which resonates to a frequency n Show Answer


Q276) A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Q are at distance of 2m and 3m respectively from the source. The ratio of the intensities of the waves at P and Q is Show Answer


Q277) The intensity of sound gets reduced by 10% on passing through a slab. The reduction in intensity on passing through three consecutive slab is Show Answer


Q278) The extension in a string obeying Hook’s law is x. the speed of sound in the stretched string is v. if the extension in the string is increased to 1.5 x, the speed of sound will be Show Answer


Q279) If two tuning forks A and B are sounded together, they produce 4 beats per second. A is then slightly loaded with wax, they produce 2 beats when sounded again. The frequency of A is 256. The frequency of B will be Show Answer


Q280) Two whistles A and B produce notes of frequencies 660 Hz and 596 Hz respectively. There is a listener at the mid-point of the line joining them. Now the whistle B and the listener start moving with speed 30 m/s away from the whistle A. If speed of sound be 330 m/s, how many beats will be heard by the listener Show Answer


Q281) A sound wave of frequency v propagating through air with a velocity c, is reflected from a surface which is moving away from the source with a constant speed v. the frequency of the reflected wave, measured by the observed at the position of the source, is Show Answer


Q282) Two open organ pipes of length 25 cm and 25.5 cm produce 10 beat/sec. The velocity of sound will be Show Answer


Q283) The tension in a piano wire is 10N. What should be the tension in the wire to produce a note of double the frequency Show Answer


Q284) Ultrasonic waves are those waves Show Answer


Q285) A train approaches a stationary observer, the velocity of train being 1/20 of the velocity of sound. A sharp blast is blown with the whistle of the engine at equal intervals of a second. The interval between the successive blasts as heard by the observer is Show Answer


Q286) An open organ pipe is closed suddenly with the result that the second overtone of the closed pipe is found to be higher in frequency by 100 than the first overtone of the original pipe. Then the fundamental frequency of the open pipe is Show Answer


Q287) Two closed organ pipes, when sounded simultaneously gave 4 beats per sec. If longer pipe has a length of 1m. Then length of shorter pipe will be, (v=300 m/s) Show Answer


Q288) In a resonance column cist and second resonance are obtained at depths 22.7 cm and 70.2 cm. The third resonance will be obtained at a depth Show Answer


Q289) A source and listener are both moving towards each other with speed v/10, where v is the speed of sound. If the frequency of the note emitted by the source is f, the frequency heard by the listener would be nearly Show Answer


Q290) Two waves of same frequency and intensity superimpose with each other in opposite phases, then after superposition the Show Answer


Q291) Four wires of identical length, diameters and of the same material are stretched on a sonometre wire. If the ratio of their tensions is 1 : 4 : 9 : 16 then the ratio of their fundamental frequencies are Show Answer


Q292) While measuring the speed of sound by performing a resonance column experiment, a student gets the first resonance condition at a column length of 18 cm during winter. Repeating the same experiment during summer, she measures the column length to be x cm for the second resonance. Then Show Answer


Q293) Fundamental frequency of sonometer wire is n. If the length, tension and diameter of wire are tripled, the new fundamental frequency is Show Answer


Q294) When two tuning forks (fork 1 and fork 2) are sounded simultaneously, 4 beats/s are heard. Now, some tape is attached on the prong of the fork 2. When the tuning fork are sounded again, 6 beats/s are heard. If the frequency of fork 1 is 200Hz, then what was the original frequency of fork 2? Show Answer


Q295) A source of sound emits waves with frequency f Hz and speed V m/sec. Two observers move away from this source in opposite directions each with a speed 0.2 V relative to the source. The ratio of frequencies heard by the two observers will be Show Answer


Q296) A resonance air column of length 20 cm resonated with a tuning fork of frequency 250 Hz. The speed of sound in air is Show Answer


Q297) The beats are produced by two sound sources of same amplitude and of nearly equal frequencies. The maximum intensity of beats will be … that of one source Show Answer


Q298) The speed of a wave in a medium is 762 m/s. If 3600 waves are passing through a point, in the medium in 2 minutes, then its wavelength is Show Answer


Q299) The apparent frequency of a note, when a listener moves towards a stationary source, with velocity of 40 m/s is 200 Hz. When the moves away from the same source with the same speed, the apparent frequency of the same note is 160 Hz. The velocity of sound in air is (in m/s) Show Answer


Q300) Tube A has both ends open while tube B has one end closed. Otherwise they are identical. Their fundamental frequencies are in the ratio Show Answer


Q301) An air column in a pipe, which is closed at one end, will be in resonance with a vibrating body of frequency 166 Hz, if the length of the air column is Show Answer


Q302) Two pulses travel in mutually opposite directions in a string with a speed of 2.5 cm/s as shown in the figure. Initially the pulses are 10cm apart. What will be the state of the string after two seconds Show Answer


Q303) Two string A and B are slightly out tune and produces beats of frequency 5 Hz. Increasing the tension in B reduces the beat frequency to 3 Hz. If the frequency of string A is 450 Hz, calculate the frequency of string B. Show Answer


Q304) Two wires are producing fundamental notes of the same frequency. Change in which of the following factors of one wire will not produce beats between them Show Answer


Q305) An organ pipe, open from both end produces 5 beats per second when vibrated with a source of frequency 200 Hz. The second harmonic of the same pipes produces 10 beats per second with a source of frequency 420 Hz. The frequency of source is Show Answer


Q306) Two passenger trains moving with a speed of 108 km/hour cross each other. One of them blows a whistle whose frequency is 750 Hz. If sound speed is 330 m/s, then passengers sitting in the other train, after trains cross each other will hear sound whose frequency will be Show Answer


Q307) The tension in a wire is decreased by 19%. The percentage decrease in frequency will be Show Answer


Q308) n waves are produced on a string in one second. When the radius of the string is doubled and the tension is maintained the same, the number of waves produced in one second for the same harmonic will be Show Answer


Q309) A tuning fork produces waves in a medium. If the temperature of the medium changes, then which of the following will change Show Answer


Q310) A tuning fork and a sonometer wire were sounded together and produce 4 beats per second. When the length of sonometer wire is 95 cm or 100 cm, the frequency of the tuning fork is Show Answer


Q311) If the ratio of amplitude of two waves is 4 : 3. Then the ratio of maximum and minimum intensity will be Show Answer


Q312) The length of an elastic string is a metre when the longitudinal tension is 4 N and b metre when the longitudinal tension is 5 N. the length of the string in metre when longitudinal tension is 9N, is Show Answer


Q313) If the length of a closed organ pipe is 1.5 m and velocity of sound is 330 m/s, then the frequency for the second note is Show Answer


Q314) A boy is walking away from a wall towards an observer at a speed of 1 metre/sec and blows a whistle whose frequency is 680 Hz. The number of beats heard by the observer per second is (Velocity of sound in air = 340 metres/sec) Show Answer


Q315) The minimum distance of reflector surface from the source for listening the echo of sound is Show Answer


Q316) A travelling wave passes a point of observation. At this point, the time interval between successive crests is 0.2 seconds and Show Answer


Q317) In stationary wave Show Answer


Q318) The phase difference between the two particles situated on both the sides of a node is Show Answer


Q319) The minimum audible wavelength at room temperature is about Show Answer


Q320) Two identical sound A and B reach a point in the same phase. The resultant sound is C. The loudness of C is n dB higher the loudness of A. Show Answer


Q321) If the tension of sonometer’s wire increases four times then the fundamental frequency of the wire will increase by Show Answer


Q322) A sound source of frequency 170 Hz is placed near a wall. A man walking from a source towards the wall finds that there is a periodic rise and fall of sound intensity. If the speed of sound in air is 340 m/s. then distance (in metres) separating the two adjacent position of minimum intensity is Show Answer


Q323) Two sirens situated one kilometer apart are producing sound of frequency 330 Hz. An observer starts moving from one siren to the other with a speed of 2 m/s. If the speed of sound be 330 m/s, what will be the beat frequency heard by the observer Show Answer


Q324) Which of the following equation represent a progressive wave? Show Answer


Q325) A wave of wavelength 2m is reflected from a surface. If a node is formed at 3m from the surface, then at what distance from the surface another node will be formed Show Answer


Q326) The wavelength of ultrasonic waves in air is of the order of Show Answer


Q327) Two similar sonometer wires given fundamental frequencies of 500 Hz. These have same tensions. By what amount the tension be increased in one wire so that the two wires produce 5 beats/sec Show Answer


Q328) An observer is approaching a stationary source with a velocity 1/4 th of the velocity of sound. Then the ratio of the apparent frequency to actual frequency of source is Show Answer


Q329) In a closed organ pipe, the 1st resonance occurs at 50 cm. At what length of pipe, the 2nd resonance will occur Show Answer


Q330) A second harmonic has to be generated in a string of length l stretched between two rigid supports. The point where the string has to be plucked and touched are Show Answer


Q331) Two increase the frequency from 100 Hz to 400 Hz the tension in the string has to be changed by Show Answer


Q332) Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force. Mass per unit length of both the strings is same and equal to 1 g/m. When both the string vibrate simultaneously the number of beats is Show Answer


Q333) What should be the velocity of a sound source moving towards a stationary observer so that apparent frequency is double the actual frequency? (Velocity of sound is v) Show Answer


Q334) The ratio of intensities between two coherent sound sources is 4∶1. The difference of loudness in decibels (dB) between maximum and minimum intensities, on their interference in space is Show Answer


Q335) A tuning fork of frequency 512 Hz is used to produce vibrations in a sonometer wire of natural frequency 256 Hz. The wire will vibrate in Show Answer


Q336) A hollow cylinder with both sides open generates a frequency v in air. When the cylinder vertically immersed into water by half its length the frequency will be Show Answer


Q337) A stone is dropped into a well. If the depth of water below the top be h and velocity of sound in air be v, the time after which splash of sound is heard is Show Answer


Q338) A source of sound is moving with constant velocity of 20 m/s emitting a note of frequency 1000 Hz. The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him will be (Speed of sound v = 340 m/s) Show Answer


Q339) Radar waves are sent towards a moving aeroplane and the reflected wave are received. When the aeroplane is moving towards the radar, the wavelength of the wave Show Answer


Q340) If you set up the seventh harmonic on a string fixed at both ends, how many nodes and antinodes are set up in it Show Answer


Q341) Which one of the following statements is true? Show Answer


Q342) Out of following incorrect statement is Show Answer


Q343) If the temperature of the atmosphere is increased, the following character of the sound wave is effected Show Answer


Q344) An observer standing near the sea shore observes 54 waves per minute. If the wavelength of the water wave is 10m then the velocity of water wave is Show Answer


Q345) Source and observer, both start moving simultaneously from origin, one along X-axis and the other along Y-axis with speed of source equal to twice the speed of observer. The graph between the apparent frequency (n') observed by observer and time t in figure would be Show Answer


Q346) Two uniform wires are vibrating simultaneously in their fundamental notes. The tension, lengths diameters and the densities of the two wires are in the ratio 8:1, 36:35, 4:1, and 1:2 respectively. If the note of the higher pitch has a frequency 360 Hz, the number of beats produced per second is Show Answer


Q347) Fundamental frequency of a sonometer wire is n. if the length and diameter of the wire are doubled keeping the tension same, then the new fundamental frequency is Show Answer


Q348) The ratio of the sound in oxygen to that in hydrogen at same temperature and pressure is approximately Show Answer


Q349) An open pipe is suddenly closed at one end with the result that the frequency of third harmonic of the closed pipe is found to be higher at 100 Hz. The fundamental frequency of the open pipe is Show Answer


Q350) 50 tuning forks are arranged in increasing order of their frequencies such that each gives 4 beats/sec with its previous tuning fork. If the frequency of the last fork is octave of the first, then the frequency of the frequency of the first tuning fork is Show Answer


Q351) Under identical conditions of pressure and density, the speed of sound is highest in a Show Answer


Q352) An observer standing at station observes frequency 219 Hz when a train approaches and 184 Hz when train goes away from him. If velocity of sound in air is 340 m/s, then velocity of train and actual frequency of whistle will be Show Answer


Q353) The tones that are separated by three octaves have a frequency ratio of Show Answer


Q354) A source of sound is travelling towards a stationary observer. The frequency of sound heard by the observer is of three times the original frequency. The velocity of sound is v m/sec. The speed of source will be Show Answer


Q355) Two wires made up of the same material are of equal length but their radii are in the ratio of 1:2. On stretching each of these two strings by the same tension, the ratio between the fundamental frequencies is Show Answer


Q356) Of the following, the equation of plane progressive wave is Show Answer


Q357) If two waves of the same frequency and amplitude respectively on superposition produce a resultant disturbance of the same amplitude, the waves differ in phase by Show Answer


Q358) A is singing a note and at the same time B is singing a note with exactly one-eight the frequency of the note of A. The energies of two sounds are equal, the amplitude of the note of B is Show Answer


Q359) Maximum number of beats frequency heard by a human being is Show Answer


Q360) Which of the following is the longitudinal wave? Show Answer


Q361) At a certain instant a stationary transverse wave is found to have maximum kinetic energy. The appearance of string at that instant is Show Answer


Q362) Transverse waves of same frequency are generated in two steel wires A and B. The diameter of A is twice of B and the tension in A is half that in B. The ratio of velocities of wave in A and B is Show Answer


Q363) If the tension and diameter of a sonometer wire of fundamental frequency n are doubled and density is halved then its fundamental frequency will become Show Answer


Q364) The echo of a gun shot is heard 8 sec. after the gun is fired. How far from him is the surface that reflects the sound (velocity of sound in air =350 m/s) Show Answer


Q365) If v is the speed of sound in air then the shortest length of the closed pipe which resonates to a frequency v, is Show Answer


Q366) If in an experiment for determination of velocity of sound by resonance tube method using a tuning fork of 512 Hz, first resonance was observed at 30.7 cm and second was obtained at 63.2 cm, then maximum possible error in velocity of sound is (consider actual speed of sound in air is 332 m/s) Show Answer


Q367) If the speed of a wave doubles as it passes from shallow water deeper water, its wavelength will be Show Answer


Q368) A string is stretched between fixed points separated by 75.0 cm. it is observed to have resonant frequency of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. Then, the lowest resonant frequency for this string is Show Answer


Q369) A standing wave is produced in a string fixed at both ends. In this case Show Answer


Q370) In a closed organ pipe the frequency of fundamental note is 50 Hz. The note of which of the following frequencies will not be emitted by it Show Answer


Q371) Two wires are fixed in a sonometer. Their tensions are in the ratio 8:1. The lengths are in the ratio 36:35. The diameters are in the ratio 4:1. Densities of the materials are in the ratio 1:2. If the higher frequency in the setting is 360 Hz, the beat frequency when the two wires are sounded together, is Show Answer


Q372) A man sets his watch by whistle that is 2 km away. How much will his watch be in error. (speed of sound in air 330 m/sec) Show Answer


Q373) In the musical octave ‘Sa’, ‘Re’, ‘Ga’ Show Answer


Q374) Sound waves of wavelength greater than that of audible sound are called Show Answer


Q375) A racing car moving towards a cliff sounds its horn. The driver observes that the sound reflected from the actual sound of the horn. If v is velocity of sound, the velocity of the car is Show Answer


Q376) Velocity of sound in air is Show Answer


Q377) 16 tuning forks are arranged in the order of increasing frequencies. Any two successive forks give 8 beats per sec when sounded together. If the frequency of the last fork is twice the first, then the frequency of the first fork is Show Answer


Q378) Two tuning forks have frequencies 380 and 384 hz respectively. When they are sounded together, they produce 4 beats. After hearing the maximum sound, how long will it take to hear the minimum sound Show Answer


Q379) Transverse waves can propagate in Show Answer


Q380) The harmonic which are present in a pipe open at one end are Show Answer


Q381) The loudness and pitch of a sound depends on Show Answer


Q382) Two sound waves of wavelengths 5m and 6m formed 30 beats in 3 seconds. The velocity of sound is Show Answer


Q383) A wave in a string has an amplitude of 2 cm. The wave travels in the +ve direction of x axis with a speed of 128 m/sec and it is noted that 5 complete waves fit in 4 m length of the string. The equation describing the wave is Show Answer


Q384) When a sound wave of frequency 300 Hz passes through a medium, the maximum displacement of a particle of the medium is 0.1 cm. the maximum velocity of the particle is equal to Show Answer


Q385) A man sitting in a moving train hears the whistle of the engine. The frequency of the whistle is 600 Hz Show Answer


Q386) Water waves are Show Answer


Q387) The first overtone of a stretched wire of given length is 320 Hz. The first harmonic is Show Answer


Q388) How many times more intense is a 60 dB sound than a dB sound? Show Answer


Q389) Velocity of sound measured in hydrogen and oxygen gas at a given temperature will be in the ratio Show Answer


Q390) Two waves having sinusoidal waveforms have different wavelengths and different amplitude. They will be having Show Answer


Q391) Two closed pipes produce 10 beats per second when emitting their fundamental nodes. If their lengths are in ratio of 25 : 26. Then their fundamental frequency in Hz, are Show Answer


Q392) Which of the following equations represents a wave travelling along y-axis? Show Answer


Q393) The frequency of a sonometer wire is 100 Hz. When the weights producing the tension are completely immersed in water, the frequency becomes 80 Hz and on immersing the weights in a certain liquid, the frequency becomes 60 Hz. The specific gravity of the liquid is Show Answer


Q394) The harmonics which are present in a pipe, open at one end are Show Answer


Q395) An organ pipe, open at both ends produces 5 beats/s when vibrates with a source of frequency 200 Hz. The second of the same pipe produces 10 beats/s with a source of frequency 420 Hz. The frequency of source is Show Answer


Q396) In the experiment for the determination of the speed of sound in air using the resonance column the resonates in the fundamental mode, with a tuning fork is 0.1m. When this length is changed to 0.35 m, the same tuning fork resonates with the first overtone. Calculate the end correction. Show Answer


Q397) Choose the correct statement Show Answer


Q398) The fractional change in wavelength of light coming from a star is 0.014% what is its velocity? Show Answer


Q399) The frequency of a tuning fork is 384 per second and velocity of sound in air is 352 m/s. How far the sound has traversed while fork completes 36 vibration Show Answer


Q400) If the temperature increases, then what happens to the frequency of the sound produced by the organ pipe Show Answer


Q401) An open organ pipe has fundamental frequency 100 Hz. What frequency will be produced if its one end is closed? Show Answer


Q402) A glass tube 1.5 m long and open at both ends, is immersed vertically in a water tank completely. A tuning fork of 660 Hz is vibrated and kept at the upper end of the tube and the tube is gradually raised out of water. The total number of resonances heard before the tube comes out of water, taking velocity of sound air 330 m/sec is Show Answer


Q403) The minimum intensity of sound is zero at a point due to two sources of nearly equal frequencies, when Show Answer


Q404) Energy is not carried by which of the following waves Show Answer


Q405) Ultrasonic waves are produced by Show Answer


Q406) When a guitar string is sounded with a 440 Hz tuning fork, a beat frequency of 5 Hz is heard. If the experiment is repeated with a tuning fork of 437 Hz, the beat frequency is 8 Hz. The string frequency (Hz) is Show Answer


Q407) A man standing on a cliff claps his hand hears its echo after 1 sec. If sound is reflected from another mountain and velocity of sound in air is 340 m/sec. Then the distance between the man and reflection point is Show Answer


Q408) A closed organ pipe and an open organ pipe are tuned to the same fundamental frequency. The ratio of their length is Show Answer


Q409) An observer is moving towards the stationary source of sound, then Show Answer


Q410) Fundamental frequency of pipe is 100 Hz and other two frequencies are 300 Hz and 500 Hz, then Show Answer


Q411) The type of waves that can be propagated through solid is Show Answer


Q412) With what velocity an observer should move relative to a stationary source so that he hears a sound of double the frequency of source Show Answer


Q413) An organ pipe open at one end is vibrating in first overtone and is in resonance with another pipe open at both ends and vibrating in third harmonic. The ratio of length of two pipe is Show Answer


Q414) Suppose that the speed of sound in air at a given temperature is 400 m/sec. An engine blows a whistle at 1200 Hz frequency. It is approaching an observer at the speed of 100 m/sec. What is the apparent frequency as heard by the observer Show Answer


Q415) Standing waves are produced in a 10 m long stretched string. If the string vibrates in 5 segments and the wave velocity is 20 m/s, the frequency is Show Answer


Q416) A string vibrates with a frequency of 200 Hz. When its length is doubled and tension is altered, it begins to vibrate with a frequency of 300 Hz. The ratio of the new tension to the original tension is Show Answer


Q417) A siren emitting sound of frequency 800 Hz is going away from a static listener with a speed of 30 m/s, frequency of the sound to be heard by the listener is (take velocity of sound as 330 m/s) Show Answer


Q418) An empty vessel is partially filled with water, then the frequency of vibration of air column in the vessel Show Answer


Q419) In a resonance pipe the first and second resonance are obtained at depths 22.7 cm and 70.2 cm respectively. What will be the end correction? Show Answer


Q420) Two trains, one coming towards and another going away from an observer both at 4 m/s produce whistle simultaneously of frequency 300 Hz. Find the number of beats produced Show Answer


Q421) When a stationary wave is formed then its frequency is Show Answer


Q422) In open organ pipe, if fundamental frequency is v, then the other frequencies are Show Answer


Q423) A tube closed at one end and containing air is excited. It produces the fundamental note of frequency 512 Hz. If the same tube is open at both the ends the fundamental frequency that can be produced is Show Answer


Q424) When a longitudinal wave propagates through a medium, the particles of the medium execute simple harmonic oscillations about their mean positions. These oscillations of a particle are characterised by an invariant Show Answer


Q425) An organ pipe is closed at one end has fundamental frequency of 1500 Hz. The maximum number of overtones generated by this pipe which a normal person can hear is Show Answer


Q426) A man fires a bullet standing between two cliffs. First echo is heard after 3 seconds and second echo is heard after 5 seconds. If the velocity of sound is 330 m/s, then the distance between the cliffs is Show Answer


Q427) A bomb explodes on the moon. How long will it take for the sound to reach the earth? Show Answer


Q428) A string fixed at both the ends is vibrating in two segments. The wavelength of the corresponding wave is Show Answer


Q429) A pipe closed at one end and open at the other end, resonate with sound waves of frequency 135 Hz and also 165 Hz, But not with any wave of frequency intermediate between these two. Then the frequency of the fundamental note is Show Answer


Q430) In meld's experiment in the transverse mode, the frequency of the tuning fork and the frequency of the waves in the string are in the ratio Show Answer


Q431) Source of sound and the observer are mutually at rest. If speed of sound is changed, then the frequency of sound heard by the observer will appear to be Show Answer


Q432) In a resonance tube, using a tuning fork of frequency 325 Hz, two successive resonance length are observed as 25.4 cm and 77.4 cm respectively. The velocity of sound in air is Show Answer


Q433) In a resonance tube, using a tuning fork of frequency 325 Hz, two successive resonance lengths are observed as 25.4 cm and 77.4 cm respectively. The velocity of sound in air is Show Answer


Q434) A wave of frequency 100 Hz is sent along a string towards a fixed end. When this wave travels back, after reflection, a node is formed at a distance of 10 cm from the fixed end of the string. The speeds of incident (and reflected) waves are Show Answer


Q435) A column of air of length 50 cm resonates with a stretched string of length 40 cm. The length of the same air column which will resonates with 60 cm of the same string at a the same tension is Show Answer


Q436) A stone is dropped into a lake from a tower 500 metre high. The sound of the splash will be heard by the man approximately after Show Answer


Q437) A string in a musical instrument is 50 cm long and its fundamental frequency is 800 Hz. If a frequency of 1000 Hz is to be produced, the required length of string is Show Answer


Q438) Which of the following do not require medium for transmission? Show Answer


Q439) If source and observer both are relatively at rest and if speed of sound is increased then frequency heard by observer will Show Answer


Q440) The wavelength of light observed on the earth from a moving star is found to decrease by 0.05%. the star is Show Answer


Q441) The Doppler's effect is applicable for Show Answer


Q442) A tuning fork arrangement (pair) produces 4 beats/sec with one fork of frequency 288 cps. A little wax is placed on the unknown fork and it then produces 2 beats/sec. The frequency of the unknown fork is Show Answer


Q443) A source of sound of frequency 256 Hz is moving rapidly towards a wall with a velocity of 5m/s. The speed of sound is 330 m/s. If the observer is between the wall and the source, then beats per second heard will be Show Answer


Q444) An organ pipe open at one end is vibrating in first overtone and is in resonance with another pipe open at both ends and vibrating in third harmonic. The ratio of length of two pipe is Show Answer


Q445) Doppler phenomena is related with Show Answer


Q446) A light pointer fixed to one prong of a tuning fork touches a vertical plate. The fork is set vibrating and the plate is allowed to fall freely. If eight oscillations are counted when the plate falls through 10 cm, the frequency of the tuning fork is Show Answer


Q447) In two similar wires of tension 16 N and T, 3 beats are heard, then T= Show Answer


Q448) A set of 24 tuning fork are so arranged that each gives 6 beats/s with the previous one. If the frequency of the last tuning fork is double that of the first, frequency of the second tuning fork is Show Answer


Q449) The number of waves contained in unit length of the medium is called Show Answer


Q450) Two sound waves with wavelengths 5.0 m and 5.5 m respectively, each propagate in a gas with velocity 330 m/s We expect the following number of beats per second Show Answer


Q451) The distance between two consecutive crests in a wave train produced in a string in 5 cm. If 2 complete waves pass through any point per second, the velocity of the wave is Show Answer


Q452) Two waves of wavelengths 50 cm and 51 cm produced 12 beats per second. The velocity of sound is Show Answer


Q453) In an experiment, it was found that string vibrates in n loops when a mass M is placed o the pan. What mass should be placed on the pa to make it vibrate in 2n loops, with same frequency. Neglect the mass of the pan. Show Answer


Q454) A sonometer wire 100 cm long has a fundamental frequency of 330 Hz. The velocity of propagation of transverse waves on the wire is Show Answer


Q455) A heavy uniform rope changes vertically from the ceiling, with its lower end free. A disturbance on the rope travelling upwards from the lower end has a velocity v at a distance x from the lower end such that Show Answer


Q456) Two wires of the same material and radii r and 2r respectively are velded together end to end. The combination is used as a sonometer wire and kept under tension T. The welded point is midway between the two bridges. When stationary waves are set up in the composite wire, the joint is a node. Then the ratio of the number of loops formed in the thinner to thicker wire is Show Answer


Q457) Sound velocity is maximum in Show Answer


Q458) The intensity of sound wave while passing through an elastic medium falls down by 10% as it covers one metre distance through the medium. If the initial intensity of the sound wave was 100 decibels, its value after it has passed through 3 metre thickness of the medium will be Show Answer


Q459) In the experiment to determine the speed of sound using a resonance column Show Answer


Q460) Two waves are approaching each other with a velocity of 20 m/s and frequency n. The distance between two consecutive nodes is Show Answer


Q461) If you set up the seven overtone on a string fixed at both ends, how many nodes and antinodes are set up in it? Show Answer


Q462) The distance between the nearest node and antinode in a stationary wave is Show Answer


Q463) An open pipe resonates with a tuning fork of frequency 500 Hz. It is observed that two successive nodes are formed at distance 16 and 46 cm from the open end. The speed of sound in air in the pipe is Show Answer


Q464) A closed Organ pipe and an open organ pipe of same length produce 2 beats/second while vibrating in their fundamental modes. The length of the open organ pipe is halved and that of closed pipe is doubled. Then the number of beats produced per second while vibrating in the fundamental mode is Show Answer


Q465) Find the frequency of minimum distance between compression & rarefaction of a wire. If the length of the wire is 1 m & velocity of sound in air is 360 m/s Show Answer


Q466) The intensity of sound increases at night due to Show Answer


Q467) 25 tuning forks arranged in series in the order of decreasing frequency. Any two successive forks produce 3 beats/sec. If the frequency of the first tuning fork is the octave of the last fork, then the frequency of the 21st fork is Show Answer


Q468) The length of a sonometer wire AB is 110 cm. Where should the two bridges be placed from A to divide the wire in three segments whose fundamental frequencies are in the ratio of 1:2:3 Show Answer


Q469) Stationary waves are set up in air column. Velocity of sound in air is 330 m/s and frequency is 165 Hz. Then distance between the nodes is Show Answer


Q470) A car sounding a horn of frequency 1000 Hz passes an observer. The ratio of frequencies of the horn noted by the observer before and after passing of the car is 11 : 9. If the speed of sound is v, the speed of the car is Show Answer


Q471) The wavelength of infrasonics in air is of the order of Show Answer


Q472) The length of a sonometer wire tuned to a frequency of 250 Hz is 0.60 metre. The frequency of tuning fork with which the vibrating wire will be in tune when the length is made 0.40 metre is Show Answer


Q473) It is possible to hear beats from the two vibrating sources of frequency Show Answer


Q474) A sound absorber attenuates the sound level by 20 dB. The intensity decreases by a factor of Show Answer


Q475) A source and an observer move away from each other with a velocity of 10 m/s with respect to ground. If the observer finds the frequency of sound coming from the source as 1950 Hz, then actual frequency of the source is (velocity of sound in air = 340 m/s) Show Answer


Q476) An earthquake generates both transverse (S) and longitudinal (P) sound waves in the earth. The speed of S waves is about 4.5 km/s and that of P waves is about 8.0km/s. A seismograph records P and S waves from an earthquake. The first P wave arrives 4.0 min before the first S wave. The epicenter of the earthquake is located at a distance about Show Answer


Q477) A source of sound emitting a tone of frequency 200 Hz moves towards an observer with a velocity v equal to the velocity of sound. If the observer also moves away from the source with the same velocity v, the apparent frequency heard by the observer is Show Answer


Q478) A sound wave of frequency n travels horizontally to the right. It is reflected from a large vertical plane surface moving to the left with speed v. The speed of the sound in the medium is c. Then Show Answer


Q479) A wave is reflected from a rigid support. The change in phase on reflection will be Show Answer


Q480) An open pipe of length 33 cm resonates with frequency of 100 Hz. If the speed of sound is 330 m/s, then this frequency is Show Answer


Q481) Two tuning forks have frequencies 450 Hz and 454 Hz respectively. On sounding these forks together, the time interval between successive maximum intensities will be Show Answer


Q482) In a medium sound travels 2 km in 3 sec and in air, it travels 3 km in 10 sec. The ratio of the wavelengths of sound in the two media is Show Answer


Q483) Velocity of sound is maximum in Show Answer


Q484) The fundamental frequency of a sonometre wire is n. If its radius is doubled and its tension becomes half, the material of the wire remains same, the new fundamental frequency will be Show Answer


Q485) If the velocity of sound in air is 350 m/s. Then the fundamental frequency of an open organ pipe of length 50 cm, will be Show Answer


Q486) If the pressure amplitude in a sound wave is tripled, then the intensity of sound is increased by a factor of Show Answer


Q487) A police car with a siren of frequency 8 kHz is moving with uniform velocity 36 km/h towards a tall building which reflects the sound waves. The speed of sound in air is 320 m/s. the frequency of the siren heard by the car driver is Show Answer


Q488) If the amplitude of sound is doubled and the frequency reduced to one-fourth, the intensity of sound at the same point will be Show Answer


Q489) When two sinusoidal waves moving at right angles to each other superimpose, they produce Show Answer


Q490) Two stretched strings of same material are vibrating under same tension in fundamental mode. The ratio of their frequencies is 1 : 2 and ratio of the length of the vibrating segments is 1 : 4. Then the ratio of the radii of the strings is Show Answer


Q491) A 20 cm long string, having a mass of 1.0 g, is fixed at both the ends. The tension in the string is 0.5 N. the string is set into vibration using an external vibrator of frequency 100 Hz. Find the separation (in cm) between the successive nodes on the string Show Answer


Q492) The equation of a cylindrical progressive wave is Show Answer


Q493) The sound carried by air from a sitar to a listener is a wave of the following type Show Answer


Q494) A spherical source of power 4 W and frequency 800 Hz is emitting sound waves. The intensity of waves at a distance 200 m is Show Answer


Q495) The velocity of waves in a string fixed at both ends is 2 m/s. The string forms standing waves with nodes 5.0 cm apart. The frequency of vibration of the string in Hz is Show Answer


Q496) 'SONAR' emits which of the following waves Show Answer


Q497) When an engine passes near to a stationary observer then its apparent frequencies occurs in the ratio 5/3. If the velocity of engine is (Velocity of sound is 340 m/s) Show Answer


Q498) Beats are produced with the help of two sound waves of amplitudes 3 and 5 units. The ratio of maximum to minimum intensity in the beats isBeats are produced with the help of two sound waves of amplitudes 3 and 5 units. The ratio of maximum to minimum intensity in the beats is Show Answer


Q499) A pulse or a wave train travels along a stretched string and reaches the fixed end of the string. It will be reflected back with Show Answer


Q500) The time of reverberation of a room A is one second. What will be the time (in seconds) of reverberation of a room, having all the dimensions double of those of room A Show Answer


Q501) Two wires made up of same material are of equal lengths but their radii are in the ratio 1:2. On stretching each of these two string by the same tension, the ratio between the fundamental frequencies is Show Answer


Q502) The equation of a spherical progressive wave is Show Answer


Q503) A source and an observer are moving towards each other with a speed equal to v/2 where v is the speed of sound. The source is emitting sound of frequency n. The frequency heard by the observer will be Show Answer


Q504) A string is hanging from a rigid support. A transverse pulse is excited at its free end. The speed at which the pulse travels a distance x is proportional to Show Answer


Q505) The frequency of fundamental tone in an open organ pipe of length 0.48 m is 320 Hz. Speed of sound is 320 m/sec. Frequency of fundamental tone in closed organ pipe will be Show Answer


Q506) A stationary point source of sound emits sound uniformly in all directions in a non-absorbing medium. Two points P and Q are at a distance of 4m and 9m respectively from the source. The ratio of amplitudes of the waves at P and Q is Show Answer


Q507) Walls of auditorium should be Show Answer


Q508) A micro-wave and an ultrasonic sound wave have the same wavelength. Their frequencies are in the ratio (approximately) Show Answer


Q509) A uniform wire of length L, diameter D and density S is stretched under a tension T. the correct relation between its fundamental frequency f, the length L and the diameter D is Show Answer


Q510) In 1 m long open pipe what is the harmonic of resonance obtain with a tuning fork of frequency 480 Hz? Show Answer


Q511) The frequency of a stretched uniform wire under tension is in resonance with the fundamental frequency of a closed tube. If the tension in the wire is increased by 8 N, it is in resonance with the first overtone of the closed tube. The initial tension in the wire is Show Answer


Q512) If the length of a closed organ pipe is 1m and velocity of sound is 330 m/s, then the frequency for the second note is Show Answer


Q513) A particle on the trough of a wave at any instant will come to the mean position after a time (T = time period) Show Answer


Q514) An open organ pipe of length / vibrates in its fundamental mode. The pressure vibration is maximum Show Answer


Q515) A tuning fork gives 5 beats with another tuning fork of frequency 100 Hz. When the first tuning fork is loaded with wax, then the number of beats remains unchanged, then what will be the frequency of the first tuning fork Show Answer


Q516) Two waves coming from two coherent sources, having different intensities interfere their ratio of maximum intensity to the minimum intensity is 25. The intensities of the sources are in the ratio Show Answer


Q517) To raise the pitch of a stringed musical instrument the player can Show Answer


Q518) Frequency of a sonometer wire is n. Now its tension is increased 4 times and its length is doubled then new frequency will be Show Answer


Q519) A closed organ pipe has fundamental frequency 100 Hz. What frequency will be produced, if its other end is also opened? Show Answer


Q520) Sound waves in air always longitudinal because Show Answer


Q521) The first overtone in a closed pipe has a frequency Show Answer


Q522) An observer moves towards a stationary source of sound of frequency n. The apparent frequency heard by him is 2n. If the velocity of sound in air is 332 m/sec, then the velocity of the observer is Show Answer


Q523) The following phenomenon cannot be observed for sound waves Show Answer


Q524) A source emits a sound of frequency of 400 Hz, but the listener hearts its 390 Hz. Then Show Answer


Q525) An open pipe of length l vibrates in fundamental mode. The pressure variation is maximum at Show Answer


Q526) An observer is moving away from source of sound of frequency 100 Hz. This speed is 33 m/s. If speed of sound is 330 m/s, then the observed frequency is Show Answer


Q527) A tuning fork produced 4 beats/s when sounded with a sonometer wire of vibrating length is 50 cm. what is the frequency of the tuning fork? Show Answer


Q528) In Melde's experiment, three loops are formed by putting a weight of 8 g in a massless pan. The weight required to form two loop is
Show Answer


Q529) The fundamental note produced by a closed organ pipe is of frequency f. The fundamental note produced by an open organ pipe of same length will be of frequency Show Answer


Q530) The tension of a stretched string is increased by 69%. In order to keep its frequency of vibration constant, its length must be increased by Show Answer


Q531) Oxygen is 16 times heavier than hydrogen. Equal volumes of hydrogen and oxygen are mixed. The ratio of speed of sound in the mixture to that in hydrogen is Show Answer


Q532) A point source emits sound equally in all direction in a non-absorbing medium. Two points P and Q are at distance of 2 and 3 m respectively from the source. The ratio of the intensities of the wave at P and Q is. Show Answer


Q533) Sound waves travel at 350 m/s through a warm air and at 3500 m/s through brass. The wavelength of a 700 Hz acoustic wave as it enters brass from warm air Show Answer


Q534) When the length of the vibrating segment of a sonometer wire is increased by 1% the percentage changes its frequency is Show Answer


Q535) Two speakers connected to the same source of fixed frequency are placed 2.0 m apart in a box. A sensitive microphone placed at a distance of 4.0m from their midpoint along the perpendicular bisector shows maximum response. The box is slowly rotated until the speakers are in line with the microphone. The distance between the midpoint of the speakers and the microphone remains unchanged. Exactly five maximum responses are observed in the microphone in doing this. The wavelength of the sound wave is Show Answer


Q536) A tuning fork makes 256 vibrations per second in air. When the velocity of sound is 330 m/s, then wavelength of the tone emitted is Show Answer


Q537) If separation between screen and source is increased by 2% what would be the effect on the intensity Show Answer


Q538) A transverse wave of amplitude 0.5 m and wavelength 1 m and frequency 2 Hz is is propagating in a string in the negative x-direction. The expression for this wave is Show Answer


Q539) A plane EM wave of frequency 30 MHz travels in free space along the x-direction. The electric field component of the wave at a particular point of space and time E = 6 V/m along y-direction. Its magnetic field component B at this point would be Show Answer


Q540) In sine wave, minimum distance between 2 particles always having same speed is Show Answer