Practice Test


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


2) Longitudinal waves cannot be propagated through:


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


4) Sound travels in rocks are in the form of:


5) The longitudinal and transverse waves can be distinguished by studying the property of:


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


7) 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:


8) 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:


9) 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:


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


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


12) The essential properties of a medium for the propagation of mechanical waves are:


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


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


15) 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:


16) 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:


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


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


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


20) 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:


21) 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:


22) 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?


23) 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:


24) 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:


25) 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:


26) 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:


27) 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:


28) 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:


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


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


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


32) 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:


33) 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:


34) 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:


35) 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):


36) 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):


37) 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:


38) 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:


39) 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:


40) 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:


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


42) Ultrasonics are used for stirring liquid solutions in order to produce:


43) The wall of hall for a cinema shows should:


44) 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:


45) 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:


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


47) 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?


48) 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.


49) 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:


50) 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:


51) 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:


52) Resonance is a special case of:


53) Which waves are used in sonography?


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


55) If a wave enters from air to water, then what remains unchanged?


56) 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?


57) 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?


58) 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:


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


60) In stationary wave the strain is:


61) 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:


62) 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:


63) 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:


64) 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.


65) If the intensity of sound is doubled, the sound level will increase by nearly:


66) 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?


67) 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:


68) 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):


69) 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:


70) The number of waves contained in a unit length of the medium is called:


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


72) 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:


73) 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?


74) Mechanical waves on the surface of a liquid are:


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


76) 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?


77) 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?


78) 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:


79) Which one is not produced by sound waves in air?


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


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


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


83) Energy is not carried by:


84) Which of the following emits sound of highest pitch?


85) 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:


86) 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.


87) 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:


88) The velocity of sound is greatest in:


89) The Doppler's effect is applicable for:


90) 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:


91) 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:


92) 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:


93) 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


94) The velocity of sound in air depends upon:


95) 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:


96) 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:


97) 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?


98) 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?


99) 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:


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


101) 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:


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


103) 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:


104) 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):


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


106) Which of the following is not a transverse wave?


107) 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:


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


109) 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?


110) 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):


111) 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:


112) 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:


113) 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:


114) In a stationary waves are variation in pressure at nodes is:


115) 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.


116) 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:


117) Wall of auditorium should be:


118) Quality of sound depends upon:


119) 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:


120) 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:


121) 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:


122) Apparatus used to find out velocity of sound in gas is:


123) If fundamental frequency of closed pipe is 50 Hz, then frequency of second overtone is:


124) 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):


125) The waves produced by a motorboat, sailing in water, are:


126) 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:


127) Which of the following emit a pure sine wave?


128) When tuning fork is vibrating the vibrations of two tuning prongs:


129) 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:


130) 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:


131) 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:


132) 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:


133) 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.


134) 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:


135) 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:


136) 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?


137) 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:


138) 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:


139) 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:


140) 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.


141) 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:


142) An increase in intensity level of one decibel implies an increase in intensity of


143) 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:


144) 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:


145) 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:


146) 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:


147) 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:


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


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


150) 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:


151) 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:


152) 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:


153) When stationary waves are set up:


154) 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?


155) 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:


156) 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:


157) The propagation constant or angular wave number is


158) 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?


159) 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.


160) 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


161) Then n = ?


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


163) Calculate the frequency of the sound as detected by the target.


164) 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.


165) In a mechanical longitudinal wave, the particles of the medium


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


167) Shock waves are produced by objects


168) 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


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


170) 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)


171) 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?


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


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


174) 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


175) 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.


176) 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.


177) Wave speed of louder wave is :


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


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


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


181) Which of the following is a mechanical wave?


182) When a wave passes from one medium to another, there is change in


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


184) 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


185) 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


186) 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


187) 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


188) 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


189) 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.


190) 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.


191) The amplitude of each component wave is


192) The separation between two consecutive nodes is


193) The end point x = 0 is


194) 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


195) 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


196) Quality of a musical note depends on


197) 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


198) 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


199) 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?


200) 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


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


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


203) 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


204) On which principle does sonometer works?


205) The intensity ratio of two waves is 1:9. The ratio of their amplitudes, is


206) 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


207) The musical interval between two tones of frequencies 320 Hz and 240 Hz is


208) 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


209) 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?


210) The sound wave was produced in a gas is always


211) 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


212) 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


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


214) 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


215) In a stationary wave all the particles


216) 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


217) 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?


218) 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


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


220) 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)


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


222) 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


223) Which of the following functions represent a wave?


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


225) 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


226) 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:


227) 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


228) When temperature increases, the frequency of a tuning fork


229) When we hear a sound, we can identify its source from


230) 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


231) 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


232) 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


233) 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 :


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


235) 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


236) 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.


237) 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


238) 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)


239) 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


240) 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)


241) Speed of sound at constant temperature depends on


242) The angle between particle velocity and wave velocity in a transverse wave is


243) 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


244) 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


245) 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


246) The ratio of speed of sound in nitrogen and helium gas at 300 K is


247) A device used for investigating the vibration of a fixed string of wire is


248) Which of the following equations represents a wave?


249) 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


250) 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)


251) 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


252) 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?


253) What is the phase difference between two successive crests in the wave?


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


255) 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


256) 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


257) Learned Indian classical vocalists do not like the accompaniment of a harmonium because


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


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


260) When two sound waves are superimposed, beats are produced when they have


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


262) 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


263) 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


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


265) 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


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


267) If T is the reverberation time of an auditorium of volume V then


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


269) 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


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


271) 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


272) 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)


273) 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


274) 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


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


276) 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


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


278) 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


279) 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


280) 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


281) 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


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


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


284) Ultrasonic waves are those waves


285) 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


286) 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


287) 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)


288) 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


289) 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


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


291) 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


292) 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


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


294) 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?


295) 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


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


297) 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


298) 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


299) 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)


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


301) 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


302) 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


303) 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.


304) 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


305) 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


306) 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


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


308) 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


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


310) 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


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


312) 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


313) 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


314) 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)


315) The minimum distance of reflector surface from the source for listening the echo of sound is


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


317) In stationary wave


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


319) The minimum audible wavelength at room temperature is about


320) 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.


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


322) 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


323) 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


324) Which of the following equation represent a progressive wave?


325) 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


326) The wavelength of ultrasonic waves in air is of the order of


327) 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


328) 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


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


330) 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


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


332) 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


333) 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)


334) 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


335) 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


336) 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


337) 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


338) 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)


339) 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


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


341) Which one of the following statements is true?


342) Out of following incorrect statement is


343) If the temperature of the atmosphere is increased, the following character of the sound wave is effected


344) 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


345) 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


346) 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


347) 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


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


349) 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


350) 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


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


352) 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


353) The tones that are separated by three octaves have a frequency ratio of


354) 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


355) 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


356) Of the following, the equation of plane progressive wave is


357) 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


358) 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


359) Maximum number of beats frequency heard by a human being is


360) Which of the following is the longitudinal wave?


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


362) 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


363) 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


364) 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)


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


366) 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)


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


368) 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


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


370) 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


371) 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


372) 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)


373) In the musical octave ‘Sa’, ‘Re’, ‘Ga’


374) Sound waves of wavelength greater than that of audible sound are called


375) 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


376) Velocity of sound in air is


377) 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


378) 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


379) Transverse waves can propagate in


380) The harmonic which are present in a pipe open at one end are


381) The loudness and pitch of a sound depends on


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


383) 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


384) 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


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


386) Water waves are


387) The first overtone of a stretched wire of given length is 320 Hz. The first harmonic is


388) How many times more intense is a 60 dB sound than a dB sound?


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


390) Two waves having sinusoidal waveforms have different wavelengths and different amplitude. They will be having


391) 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


392) Which of the following equations represents a wave travelling along y-axis?


393) 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


394) The harmonics which are present in a pipe, open at one end are


395) 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


396) 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.


397) Choose the correct statement


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


399) 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


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


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


402) 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


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


404) Energy is not carried by which of the following waves


405) Ultrasonic waves are produced by


406) 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


407) 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


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


409) An observer is moving towards the stationary source of sound, then


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


411) The type of waves that can be propagated through solid is


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


413) 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


414) 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


415) 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


416) 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


417) 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)


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


419) 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?


420) 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


421) When a stationary wave is formed then its frequency is


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


423) 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


424) 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


425) 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


426) 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


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


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


429) 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


430) 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


431) 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


432) 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


433) 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


434) 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


435) 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


436) 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


437) 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


438) Which of the following do not require medium for transmission?


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


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


441) The Doppler's effect is applicable for


442) 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


443) 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


444) 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


445) Doppler phenomena is related with


446) 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


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


448) 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


449) The number of waves contained in unit length of the medium is called


450) 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


451) 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


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


453) 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.


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


455) 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


456) 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


457) Sound velocity is maximum in


458) 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


459) In the experiment to determine the speed of sound using a resonance column


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


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


462) The distance between the nearest node and antinode in a stationary wave is


463) 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


464) 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


465) 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


466) The intensity of sound increases at night due to


467) 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


468) 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


469) 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


470) 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


471) The wavelength of infrasonics in air is of the order of


472) 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


473) It is possible to hear beats from the two vibrating sources of frequency


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


475) 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)


476) 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


477) 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


478) 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


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


480) 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


481) 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


482) 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


483) Velocity of sound is maximum in


484) 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


485) 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


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


487) 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


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


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


490) 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


491) 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


492) The equation of a cylindrical progressive wave is


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


494) 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


495) 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


496) 'SONAR' emits which of the following waves


497) 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)


498) 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


499) 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


500) 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


501) 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


502) The equation of a spherical progressive wave is


503) 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


504) 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


505) 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


506) 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


507) Walls of auditorium should be


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


509) 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


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


511) 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


512) 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


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


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


515) 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


516) 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


517) To raise the pitch of a stringed musical instrument the player can


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


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


520) Sound waves in air always longitudinal because


521) The first overtone in a closed pipe has a frequency


522) 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


523) The following phenomenon cannot be observed for sound waves


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


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


526) 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


527) 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?


528) 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


529) 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


530) 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


531) 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


532) 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.


533) 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


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


535) 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


536) 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


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


538) 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


539) 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


540) In sine wave, minimum distance between 2 particles always having same speed is