Practice Test


Q1) In a double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then, in the interference pattern Show Answer


Q2) In a double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then, in the interference pattern Show Answer


Q3) Bright coiours exhibited by spider's web, exposed to sunlight, are due to Show Answer


Q4) In Young's double slit experiment, the separation between the slits is halved and the distance between the slits and the screen is doubled. The fringe width will Show Answer


Q5) In a Young's double slit experiment, constructive interference is produced at a certain point P. The intensities of light at P due to the individual sources are 4 and 9 units. The resultant intensity at point P will be Show Answer


Q6) For the constructive interference the path difference between the two interfering waves must be equal to Show Answer


Q7) A monochromatic beam of light is used for the formation of fringes on the screen by illuminating the two slits in the Young's double-slit interference experiment. When a thin film of mica is interposed in the path of one of the interference beams then Show Answer


Q8) If white light is used in Young's double slit experiment Show Answer


Q9) to demonstrate the phenomenon of interference, we require two sources which emit radiation Show Answer


Q10) Imagine a Young's double slit experiment using electron waves produced by an electron gun. To increase the width of the interference fringes. Show Answer


Q11) Two coherent beams of light of same wavelengths superpose in a certain region of space. If the intensity of one beam is 4 times that of the other, then the ratio of intensity at a bright point to that at a dark point is Show Answer


Q12) In double slit experiment, for light of which colour,, the fringe, width will be minimum ? Show Answer


Q13) Young's experiment establishes that Show Answer


Q14) When monochromatic light is replaced by white light in Fresnel's biprism arrangement, the central fringe is Show Answer


Q15) If yellow light emitted by sodium lamp in Young's double slit experiment is replaced by monochromatic blue light of the same intensity Show Answer


Q16) In Young’s experiment, the ratio of maximum to minimum intensities of the fringe system is 4:1. The amplitudes of the coherent sources are in the ratio Show Answer


Q17) The power transmitted through B is Show Answer


Q18) The phase difference introduced by the film is Show Answer


Q19) The power in watt received at the focal point F of the lens is Show Answer


Q20) In Young's slit experiment, the phase difference between the light waves reaching third bright fringe from the centra1 fringe will be Show Answer


Q21) In Young's double slit experiment on interference, the ratio of the intensities of a bright band and a dark band is 16 : 1. The ratio of the amplitudes of the interfering waves is Show Answer


Q22) In a Young's double slit experiment, 12 fringes are observed to be formed in a certain segment of the screen when light of wavelength 600 nm is used. If the wavelength of light is changed to 400 nm, number of fringes observed in the same segment of the screen is given by Show Answer


Q23) Find the wavelength of parallel beam in liquid Show Answer


Q24) Calculate the fringe width Show Answer


Q25) One of the slit of the apparatus is covered by a thin glass sheet of refractive index 1. 53. Find the smallest thickness of the sheet to bring the adjacent minimum on the axis Show Answer


Q26) What speed should a galaxy move with respect to us so that the sodium line at 589 nm is observed at 598.6 nm ? Show Answer


Q27) Two slits are made one millimeter apart and the screen is placed one meter away. What is the fringe separation when blue-green wavelength 500 nm is used ? Show Answer


Q28) Two slits are millimeter apart and the screen is placed one metre away. The wavelength of light used is 500 nm. What should be the width of each slit to obtain 10 maxima of the double-slit pattern within the central maxima of the single slit pattern Show Answer


Q29) For what distance is ray optics a good approximation when the aperture is 3 mm wide and the wavelength is 500 nm ? Show Answer


Q30) The shape fringe patterns in YDSE is Show Answer


Q31) If we replace the monochromatic source in YDSE by white light, then Show Answer


Q32) A beam of light consisting of two wavelengths 650 nm and 520 nm, is used to obtain interference fringes in a YSDE. The distance of the third bright fringe on the screen from the central maximum for wavelength 650 nm is : ( The distance between the slits is 2 mm and the distance between the plane of the slits and the screen is 120 cm ) Show Answer


Q33) In the above question, what is the least distance from the central maxima where the bright fringes due to both the wavelength coincide ? Show Answer


Q34) Estimate the distance for which ray-optics is a good approximation for an aperture of 4 mm and wavelength 400 nm. Show Answer


Q35) Two towers on top of two bills one 40 km apart. The line joining them passes 50 m above a hill halfway between the towers. What is the longest wavelength of radiowaves, which can be sent between the towers without appreciable diffraction effects. Show Answer


Q36) A parallel beam of light of wavelength 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1 m away. It is observed that the first minimum is at a distance of 2.5 mm from the centre of the screen. The width of the slit is Show Answer


Q37) Yellow light is used in a single slit diffraction experiment with slit width of 0.6 mm. If yellow light is replaced by X-rays, then the observed pattern will reveal Show Answer


Q38) Pick out the correct statements Show Answer


Q39) At the first minima, the path difference between two waves starting from the two ends of a slit in a single slit Fraunhofer diffractin experiment is Show Answer


Q40) The penetration of light into the region of geometrical shadow is called Show Answer


Q41) To observe diffraction, the size of an obstacle Show Answer


Q42) While both light and sound show wave character, diffraction ( bending round corners ) is much harder to observe in light. This is because Show Answer


Q43) Directions of the first secondary maximum in the Fraunhofer diffraction pattern at a single slit is given by ( a is the width of the slit ) Show Answer


Q44) Diffraciton effects are easier to notice in the case of sound waves than in the case of light waves because Show Answer


Q45) The wavelength of light can be experimentally found using Show Answer


Q46) In the experiment of diffraction at a single slit, if the slit width is decreased, the width of the central maximum Show Answer


Q47) The frequency of light can be experimentally found using Show Answer


Q48) Polarisation of light takes place due to many processes. Which of the following will not cause polarization ? Show Answer


Q49) Consider the following statements A and B identify the correct answer.
A. Polarised light can be used to study the helical surface of nucleic acids.
B. Optic axis is a direction and not any particular line in the crystal Show Answer


Q50) A polaroid is being used as an analyzer of plane polaroid light. In one complete rotation of the crystal, the maximum intensities will be observed only Show Answer


Q51) Only transverse waves undergo Show Answer


Q52) If a wave can be polarized, it must be Show Answer


Q53) A ray of light falls on a transparent glass plate. Part of it is reflected and part is refracted. The reflected and refracted rays can be perpendicular to each other for Show Answer


Q54) Waves that cannot be polarized are Show Answer


Q55) The angular width subtended by the two first order minima on the screen, at the slit is Show Answer


Q56) The separation between the first order minima on the screen is Show Answer


Q57) The width of the central maximum is Show Answer


Q58) Polaroid sheets are often used for making sun glasses. This is because polaroid glasses Show Answer


Q59) When light incident on a refracting surface is polarized by reflection, then angle between the refracted and reflected rays is Show Answer


Q60) The correct expression relating polarising angle and refractive index is Show Answer


Q61) The experimental proof that light is a transverse wave may be obtained through Show Answer


Q62) A parallel monochromatic beam of light is incident normally on a narrow slit. A diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam. At the first minimum of the diffraction pattern, the phase difference between the rays coming form from the two edges of the slit is Show Answer


Q63) The distance between the first and the sixth minima in the diffraction pattern of a single alit is 0.5 mm. The screen is 0.5 m away from the slit. If the wavelength of light used is 5000 Å, then the slit width will be Show Answer


Q64) A narrow slit of width 1 mm is illuminated by monochromatic light of wavelength 600 nm.The distance between the first minima on either side on a screen at a distance of 2 m is Show Answer


Q65) An astronaut is looking down on earth's surface from a space shuttle at an altitude of 400 km. Assuming that the astronaut's pupil diameter is 5 mm and the wavelength of visible light is 500 nm, the astronaut will be able to resolve linear objects of the size of about Show Answer


Q66) At the Brewster angle of incidence, the reflected light is polarised. Show Answer


Q67) The Brewster angle is Show Answer


Q68) At the Brewstar's angle Show Answer


Q69) By corpuscular theory of light, the phenomenon which can be explained is Show Answer


Q70) According to corpuscular theory of light, the different colours of light are due to Show Answer


Q71) Huygen's conception of secondary waves Show Answer


Q72) The idea of the quantum nature of light has emerged in an attempt to explain Show Answer


Q73) Two coherent sources of light can be obtained by Show Answer


Q74) By Huygen's wave theory of light, we cannot explain the phenomenon of Show Answer


Q75) Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are Show Answer


Q76) Light appears to travel in straight lines since Show Answer


Q77) The idea of secondary wavelets for the propagation of a wave was first given by Show Answer


Q78) By a monochromatic wave, we mean Show Answer


Q79) The similarity between the sound waves and light waves is Show Answer


Q80) The ratio of intensities of two waves is 9 : 1. They are producing interference. The ratio of maximum and minimum intensities will be Show Answer


Q81) A wave can transmit ........... from one place to another Show Answer


Q82) If the ratio of intensities of two waves is 1 : 25, then the ratio of their amplitudes will be Show Answer


Q83) Wave nature of light follows because Show Answer


Q84) If L is the coherence length and c the velocity of light, the coherent time is Show Answer


Q85) If the amplitude ratio of two sources producing interference is 3 : 5, the ratio of intensities at maxima and minima is Show Answer


Q86) Colours of thin films result from or On a rainy day, a small oil film on water show brilliant colours. This is due to Show Answer


Q87) Two sources of waves are called coherent if Show Answer


Q88) Soap bubble appears coloured due to the phenomenon of Show Answer


Q89) If two light waves having same frequency have intensity ratio 4 : 1 and they interfere, the ratio of maximum to minimum intensity in the pattern will be Show Answer


Q90) Evidence for the wave nature of light cannot be obtained from Show Answer


Q91) Two light sources are said to be coherent if they are obtained from Show Answer


Q92) Wavelength of light of frequency 100 Hz Show Answer


Q93) Two waves having intensity in the ratio 25 : 4 produce interference. The ratio of the maximum to the minimum intensity is Show Answer


Q94) Wavefront means Show Answer


Q95) Wavefront of a wave has direction with wave motion Show Answer


Q96) Which one of the following phenomena is not explained by Huygen's construction of wavefront Show Answer


Q97) Interference was observed in interference chamber when air was present, now the chamber is evacuated and if the same light is used, a careful observer will see Show Answer


Q98) The ratio of intensities of two waves are given by 4 : 1. The ratio of the amplitudes of the two waves is Show Answer


Q99) For the sustained interference of light, the necessary condition is that the two sources should Show Answer


Q100) If the ratio of amplitude of two waves is 4 : 3, then the ratio of maximum and minimum intensity is Show Answer


Q101) Which of the following is conserved when light waves interfere Show Answer


Q102) Intensity of light depends upon Show Answer


Q103) Ray diverging from a point source from a wave front that is Show Answer


Q104) Ratio of amplitude of interfering waves is 3 : 4. Now ratio of their intensities will be Show Answer


Q105) Newton postulated his corpuscular theory on the basis of Show Answer


Q106) The dual nature of light is exhibited by Show Answer


Q107) Coherent sources are those sources for which Show Answer


Q108) Wave nature of light is verified by Show Answer


Q109) Light waves producing interference have their amplitudes in the ratio 3 : 2. The intensity ratio of maximum and minimum of interference fringes is Show Answer


Q110) Laser beams are used to measure long distance because Show Answer


Q111) Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is 25. The intensities of the sources are in the ratio Show Answer


Q112) The frequency of light ray having the wavelength 3000Å is Show Answer


Q113) Two waves have their amplitudes in the ratio 1 : 9. The maximum and minimum intensities when they interfere are in the ratio Show Answer


Q114) Huygen's principle of secondary wavelets may be used to Show Answer


Q115) What is the path difference of destructive interference Show Answer


Q116) Intensities of the two waves of light are I and 4I. The maximum intensity of the resultant wave after superposition is Show Answer


Q117) As a result of interference of two coherent sources of light, energy is Show Answer


Q118) When a beam of light is used to determine the position of an object, the maximum accuracy is achieved if the light is Show Answer


Q119) If the distance between a point source and screen is doubled, then intensity of light on the screen will become Show Answer


Q120) Huygen wave theory allows us to know Show Answer


Q121) The wave theory of light was given by Show Answer


Q122) Which of the following phenomena can explain quantum nature of light Show Answer


Q123) Which of the following is not a property of light Show Answer


Q124) What causes changes in the colours of the soap or oil films for the given beam of light Show Answer


Q125) Select the right option in the following Show Answer


Q126) Two waves of intensity I undergo Interference. The maximum intensity obtained is Show Answer


Q127) If an interference pattern have maximum and minimum intensities in 36 : 1 ratio then what will be the ratio of amplitudes Show Answer


Q128) In the interference pattern, energy is Show Answer


Q129) In Young's double slit experiment, if the slit widths are in the ratio 1 : 9, then the ratio of the intensity at minima to that at maxima will be Show Answer


Q130) In Young's double slit interference experiment, the slit separation is made 3 fold. The fringe width becomes Show Answer


Q131) In a certain double slit experimental arrangement interference fringes of width 1.0 mm each are observed when light of wavelength 5000 Å is used. Keeping the set up unaltered, if the source is replaced by another source of wavelength 6000 Å, the fringe width will be Show Answer


Q132) In Young's double slit experiment, if one of the slit is closed fully, then in the interference pattern Show Answer


Q133) In Young's double slit experiment, a glass plate is placed before a slit which absorbs half the intensity of light. Under this case Show Answer


Q134) In Young's experiment, the distance between the slits is reduced to half and the distance between the slit and screen is doubled, then the fringe width Show Answer


Q135) In the Young's double slit experiment, the ratio of intensities of bright and dark fringes is 9. This means that Show Answer


Q136) An oil flowing on water seems coloured due to interference. For observing this effect, the approximate thickness of the oil film should be Show Answer


Q137) In Young's double slit experiment, if L is the distance between the slits and the screen upon which interference pattern is observed, x is the average distance between the adjacent fringes and d being the slit separation. The wavelength of light is given by Show Answer


Q138) In a Young's double slit experiment, the central point on the screen is Show Answer


Q139) Young's experiment is performed in air and then performed in water, the fringe width Show Answer


Q140) In double slits experiment, for light of which colour the fringe width will be minimum Show Answer


Q141) In Young's double slit experiment, if the widths of the slits are in the ratio 4 : 9, the ratio of the intensity at maxima to the intensity at minima will be Show Answer


Q142) In two separate set - ups of the Young's double slit experiment, fringes of equal width are observed when lights of wavelengths in the ratio 1 : 2 are used. If the ratio of the slit separation in the two cases is 2 : 1, the ratio of the distances between the plane of the slits and the screen in the two set - ups is Show Answer


Q143) In an interference experiment, the spacing between successive maxima or minima is Show Answer


Q144) If yellow light in the Young's double slit experiment is replaced by red light, the fringe width will Show Answer


Q145) In Young's experiment, one slit is covered with a blue filter and the other (slit) with a yellow filter. Then the interference pattern Show Answer


Q146) In Young's double slit experiment, the distance between the slits is 1 mm and that between slit and screen is 1 meter and 10th fringe is 5 mm away from the central bright fringe, then wavelength of light used will be Show Answer


Q147) In a Young’s experiment, two coherent sources are placed 0.90 mm apart and the fringes are observed one meter away. If it produces the second dark fringe at a distance of 1 mm from the central fringe, the wavelength of monochromatic light used will be Show Answer


Q148) If a torch is used in place of monochromatic light in Young's experiment what will happens Show Answer


Q149) When a thin metal plate is placed in the path of one of the interfering beams of light Show Answer


Q150) The fringe width in Young's double slit experiment increases when Show Answer


Q151) Two slits, 4mm apart, are illuminated by light of wavelength 6000 Å. What will be fringe width on a screen placed 2m from the slits Show Answer


Q152) In the Young's double slit experiment, for which colour the fringe width is least Show Answer


Q153) In a Young's double slit experiment, the separation of the two slits is doubled. To keep the same spacing of fringes, the distance D of the screen from the slits should be made Show Answer


Q154) Young's double slit experiment is performed with light of wavelength 550 nm. The separation between the slits is 1.10 mm and screen is placed at distance of 1 m. What is the distance between the consecutive bright or dark fringes Show Answer


Q155) An interference pattern was made by using red light. If the red light changes with blue light, the fringes will become Show Answer


Q156) If a white light is used in Young' double slit experiments then a very large number of coloured fringes can be seen Show Answer


Q157) In Young's double slit experiment, the distance between the two slits is made half, then the fringe width will become Show Answer


Q158) In Young's double slit experiment, the central bright fringe can be identified Show Answer


Q159) In Young's double slit experiment, the wavelength of the light used is doubled and distance between two slits is half of initial distance, the resultant fringe width becomes Show Answer


Q160) In a Young's double slit experiment, the source illuminating the slits is changed from blue to violet. The width of the fringes Show Answer


Q161) In Young's double slit experiment, the intensity of light coming from the first slit is double the intensity from the second slit. The ratio of the maximum intensity to the minimum intensity on the interference fringe pattern observed is Show Answer


Q162) If the sodium light in Young's double slit experiment is replaced by red light, the fringe width will Show Answer


Q163) In a Young’s double slit experiment, the slit separation is 1mm and the screen is 1m from the slit. For a monochromatic light of wavelength 500 nm, the distance of 3rd minima from the central maxima is Show Answer


Q164) In an interference experiment, third bright fringe are obtained at a point on the screen with a light of 700 nm. What should be the wavelength of the light source in order to obtain 5th bright fringe at the same point Show Answer


Q165) In a Young's double-slit experiment the fringe width is 0.2 mm. If the wavelength of light used is increased by 10% and the separation between the slits is also increased by 10%, the fringe width will be Show Answer


Q166) Two coherent sources of intensity ratio 1 : 4 produce an interference pattern. The fringe visibility will be Show Answer


Q167) In Young's double slit experiment the amplitudes of two sources are 3a and a respectively. The ratio of intensities of bright and dark fringes will be Show Answer


Q168) In Young's double slit experiment, a minimum is obtained when the phase difference of super imposing waves is Show Answer


Q169) In Young double slit experiment, when two light waves form third minimum, they have Show Answer


Q170) In Fresnel's biprism experiment, on increasing the prism angle, fringe width will Show Answer


Q171) If Fresnel's biprism experiment as held in water in-spite of air, then what will be the effect on fringe width Show Answer


Q172) What is the effect on Fresnel's biprism experiment when the use of white light is made Show Answer


Q173) What happens to the fringe pattern when the Young's double slit experiment is performed in water instead or air then fringe width Show Answer


Q174) In Young's doubled slit experiment, the separation between the slit and the screen increases. The fringe width Show Answer


Q175) In which of the following is the interference due to the division of wave front Show Answer


Q176) The bending of beam of light around corners of obstacles is called Show Answer


Q177) A diffraction is obtained by using a beam of red light. What will happen if the red light is replaced by the blue light Show Answer


Q178) A single slit of width 0.20 mm is illuminated with light of wavelength 500 nm. The observing screen is placed 80 cm from the slit. The width of the central bright fringe will be Show Answer


Q179) A zone plate of focal length 60cm, behaves as a convex lens, If wavelength of incident light is 6000 Å, then radius of first half period zone will be Show Answer


Q180) Conditions of diffraction is Show Answer


Q181) The radius r of half period zone is proportional to Show Answer


Q182) When light is incident on a diffraction grating the zero order principal maximum will be Show Answer


Q183) The condition for observing Fraunhofer diffraction from a single slit is that the light wavefront incident on the slit should be Show Answer


Q184) A single slit of width a is illuminated by violet light of wavelength 400 nm and the width of the diffraction pattern is measured as y. When half of the slit width is covered and illuminated by yellow light of wavelength 600 nm, the width of the diffraction pattern is Show Answer


Q185) A polariser is used to Show Answer


Q186) Light waves can be polarised as they are Show Answer


Q187) Which of following can not be polarised Show Answer


Q188) Out of the following statements which is not correct Show Answer


Q189) The transverse nature of light is shown by Show Answer


Q190) Refractive index of material is equal to tangent of polarising angle. It is called Show Answer


Q191) For the study of the helical structure of nucleic acids, the property of electromagnetic radiation generally used is Show Answer


Q192) The phenomenon of polarization of light indicates that Show Answer


Q193) A parallel monochromatic beam of light is incident normally on a narrow slit. A diffraction pattern is formed on a screen placed perpendicular to the direction of incident beam. At the first maxima of the diffraction pattern the phase difference between the rays coming from the edges of the slit is Show Answer


Q194) A diffraction pattern is obtained using a beam of red light. What happens if the red light is replaced by blue light Show Answer


Q195) A Young’s double slit set up for interference is shifted from air to within water, then the fringe width Show Answer


Q196) A single slit Fraunhofer diffraction pattern is formed with white light. For what wavelength of light the third secondary maximum in the diffraction pattern coincides with the second secondary maximum in the pattern for red light of wavelength 6500Å? Show Answer


Q197) In diffraction from a single slit, the angular width of the central maxima does not depend on Show Answer


Q198) The Young’s double slit experiment is performed with blue and with green light of wavelength 4360 Å and 5460 Å respectively. If x is the distance of 4th maxima from the central one, then Show Answer


Q199) TV waves have a wavelength range of 1-10 meter. Their frequency range in MHz is Show Answer


Q200) Which of the following cannot be polarized? Show Answer


Q201) In a biprism experiment, 5th dark fringe is obtained at a point. If a thin transparent film is placed in the path of one of waves, then 7th bright fringes is obtained at the same point. The thickness of the film in terms of wavelength l and refractive index μ will be Show Answer


Q202) The wavelength of the matter waves is independent of Show Answer


Q203) The graph showing the dependence of intensity of transmitted light on the angle between polarizer and analyser, is Show Answer


Q204) If white light is used in the Newton’s rings experiment, the colour observed in the reflected light is complementary to that observed in the transmitted light is complementary to that observed in the transmitted light through the same point. This is due to Show Answer


Q205) In the diffraction pattern of a single slit Show Answer


Q206) Two light sources are said to be coherent if they are obtained from Show Answer


Q207) Oil floating on water looks coloured due to interference of light. What should be the order of magnitude of thickness of oil layer in order that this effect may be observed? Show Answer


Q208) A point source of electromagnetic radiation has an average power output of 800 W. The maximum value of electric field at a distance 4.0 m from the source is Show Answer


Q209) If Young’s double slit experiment, is performed in water Show Answer


Q210) Which of the following shows green house effect Show Answer


Q211) In the Young’s double slit experiment, the spacing between two slits is 0.1 mm. If the screen is kept at a distance of 1.0 m from the slits and wavelength of light is 5000 Å, then the fringe width is Show Answer


Q212) Which of the following diagrams represent the variation of electric field vector with time for a circularly polarized light Show Answer


Q213) In a diffraction pattern by a wire, on increasing diameter of wire, fringe width Show Answer


Q214) In a biprism experiment, by using light of wavelength5000 Å, 5mm wide fringes are obtained on a screen 1.0 m away from the coherent sources. The separation between the two coherent sources is Show Answer


Q215) Which one of the following property of light does not support wave theory of light? Show Answer


Q216) Light waves travel in vacuum along the y – axis. Which of the following may represent the wavefront? Show Answer


Q217) A wavefront presents one, two and three HPZ at points A,B and C respectively. If the ratio of consecutive amplitudes of HPZ is 4 : 3, then the ratio of resultant intensities at these point will be Show Answer


Q218) In Young’s double slit experiment, the slits are 3 mm apart. The wavelength of light used is 5000 Å and the distance between the slits and the screen is 90 cm. The fringe width in 9 (mm) is Show Answer


Q219) Two polaroids are kept crossed to each other. Now one of them us rotated through an angle of 45°. The percentage of incident light now transmitted through the system is Show Answer


Q220) If a source of light is moving away from a stationary observer, then the frequency of light wave appears to change because of Show Answer


Q221) Two parallel slits 0.6 mm apart are illuminated by light source of wavelength 6000 Å. The distance between two consecutive dark fringes on a screen 1 m away from the slits is Show Answer


Q222) A single slit Fraunhoffer diffraction pattern is formed with white light. For what wavelength of light the third secondary maximum in the diffraction pattern coincides with the second secondary maximum in the pattern for red light of wavelength 6500 Å Show Answer


Q223) In a Young’s double slit experiment, the separation between the two slits is 0.9 mm and the fringes are observed 1 m away. If it produces the second dark fringes at a distance of 1 mm from the central fringe, the wavelength of the monochromatic source of light used is Show Answer


Q224) Through which character we can distinguish the light waves from sound waves Show Answer


Q225) In Young’s double slit experiment, the separation between the slit and the screen increases. The fringe width Show Answer


Q226) The k line of singly ionized calcium has a wavelength of 393.3 nm as measured on earth. In the spectrum of one of the observed galaxies, this spectral line is located at 401.8 nm. The speed with which the galaxy is moving away from us, will be Show Answer


Q227) The maximum distance upto which TV transmission from a TV tower of height h can be received is proportional to Show Answer


Q228) The electromagnetic waves travel with a velocity Show Answer


Q229) In Young’s double slit experiment, the separation between the slit is haled and the distance between the slits and screen is doubled. The fringe-width will Show Answer


Q230) The distance between the first dark and bright band formed in Young’s double slit experiment with band width B is Show Answer


Q231) Which of the following statements indicates that light waves are transverse Show Answer


Q232) In Young’s double slit experiment, the central bright fringe can be identified Show Answer


Q233) The observed wavelength of light coming from a distant galaxy is found to be increased by 0.5% as compared with that coming from a terrestrial source. The galaxy is Show Answer


Q234) In Fresnel’s biprism experiment is held in water instead of air, then what will be the effect on fringe width Show Answer


Q235) Two stars are situated at a distance of 8 light year from the earth. These are to be just resolved by a telescope of diameter 0.25 m. If the wavelength of light used is 5000Å, then the distance between the stars must be Show Answer


Q236) A wave is propagating in a medium of electric dielectric constant 2 and relative magnetic permeability 50. The wave impedance of such a medium is Show Answer


Q237) The angular resolution of a 10 cm diameter telescope at a wavelength of 5000Å is of the order of Show Answer


Q238) A beam of electron is used in an YDSE experiment. The slit width is d. When the velocity of electron is increased, then Show Answer


Q239) Out of the following statements which is not correct Show Answer


Q240) In Young’s double slit experiment, if one of the slits is closed fully, then in the interference pattern Show Answer


Q241) A laser beam can be focused on an area equal to the square of its wavelength, A He-Ne laser radiates energy at the rate of 1mV and its wavelength is 632.8 nm. The intensity of focussed beam will be Show Answer


Q242) A beam of light of wavelength 600 nm from a distance source falls on a single slit 1.00 mm wide and the resulting diffraction pattern is observed on a screen 2m away. The distance between the first dark fringes on either side of the central bright fringe is Show Answer


Q243) Light of wavelength 6000 Å falls on a single slit of width 0.1 mm. The second minimum will be formed for the angle of diffraction of Show Answer


Q244) The oscillating electric and magnetic vectors of an electromagnetic wave are oriented along Show Answer


Q245) Yellow light is used in single slit diffraction experiment with slit width 0.6 mm. If yellow light is replaced by X-rays, then the pattern will reveal that Show Answer


Q246) The angle of incidence at which reflected light is totally polarized for reflection from air to glass (refractive index n) is Show Answer


Q247) Which of the following waves have the maximum wavelength Show Answer


Q248) Which of the following cannot be explained on the basis of wave nature of light?
I. Polarization
II. Optical activity
III. Photoelectric effect
IV. Compton effect
Show Answer


Q249) A slit 5 cm wide is irradiated normally with microwaves of wavelength 1.0 cm. Then the angular spread of the central maximum on either side if incident light is nearly Show Answer


Q250) Which of the following phenomena can explain quantum nature of light Show Answer


Q251) The ratio of maximum and minimum intensities of two sources is 4 :1. The ratio of their amplitudes is Show Answer


Q252) In Young’s double slit experiment, if monochromatic light is replaced by white light Show Answer


Q253) When a compact disc is illuminated by small source of white light, coloured bands are observed. This is due to Show Answer


Q254) For the constructive interference the path difference between the two interfering waves must be equal to Show Answer


Q255) In Young’s double slit experiment if the slits widths are in the ratio 1 : 9, the ratio of the intensities at minima to that at maxima will be Show Answer


Q256) The ratio of intensities of consecutive maxima in the diffraction pattern due to a single slit is Show Answer


Q257) A 20 cm length of a certain solution causes right handed rotation of 38°. A 30 cm length of another solution causes left handed rotation of 24°. The optical rotation caused by 30 cm length of a mixture of the above solutions in the volume ratio 1 : 2 is Show Answer


Q258) Interference may be seen using two independent Show Answer


Q259) A stone thrown into still water, creates a circular wave pattern moving radially outwards. If r is the distance measured from the centre of the pattern, the amplitude of the wave varies as Show Answer


Q260) A signal emitted by an antenna from a certain point can be received at another point of the surface in the form of Show Answer


Q261) Angular width (β) of central maximum of a diffraction pattern on a single slit does not depend upon Show Answer


Q262) A beam of natural light falls on a system of 6 polaroids, which are arranged in succession such that each polaroid is turned through 30° with respct to the preceding one. The percentage of incident intensity that passes through the system will be Show Answer


Q263) Light of wavelength 589.3nm is incident normally on the slit of width 0.1nm. What will be the angular width of the central diffraction maximum at a distance of 1m from the slit Show Answer


Q264) Which one of the following is the property of a monochromatic, plane electromagnetic wave in free space Show Answer


Q265) In Young’s double slit experiment, distance between two sources is 0.1 mm. The distance of screen from the sources is 20 cm. Wavelength of light used is 5460 Å. Then angular position of the first dark fringe is Show Answer


Q266) What is ozone hole Show Answer


Q267) A single slit is used to observe diffraction pattern with red light. On replacing the red light with violet light the diffraction pattern would Show Answer


Q268) In Young’s double slit experiment, a third slit is made in between the double slits. Then Show Answer


Q269) Unpolarised light falls on two polarizing sheets placed one on top of the other. What must be the angle between the characteristic directions of the sheets if the intensity of the final transmitted light is one-third the maximum intensity of the first transmitted beam Show Answer


Q270) 80 g of impure sugar when dissolved in a litre of water given an optical rotation of9.9°, when placed in a tube of length 20 cm. If the specific rotation of sugar is 66°, then concentration of sugar solution will be Show Answer


Q271) The phenomenon which does not take place in sound waves is Show Answer


Q272) The speed of electromagnetic wave in vacuum depends upon the source of radiation Show Answer


Q273) The two coherent sources of equal intensity produce maximum intensity of 100 units at a point. If the intensity of one of the sources is reduced by 36% by reducing its width then the intensity of light at the same point will be Show Answer


Q274) In Young’s double slit experiment, the slit width and the distance of slits from the screen both are doubled. The fringe width Show Answer


Q275) In Young’s double slit experiment, when violet light of wavelength 4358 Å is used, the 84 fringe are seen in the field of view, but when sodium light of certain wavelength is used, then 62 fringes are seen in the field of view, the wavelength of sodium light is Show Answer


Q276) Which phenomenon best supports the theory that matter has a wave nature? Show Answer


Q277) In Young’s double slit interference pattern the fringe width Show Answer


Q278) H-polaroid is prepared by Show Answer


Q279) If an interference pattern has maximum and minimum intensities in 36 : 1 ratio then what will be the ratio of amplitudes Show Answer


Q280) Two Nicols are oriented with their principal planes making an angle of 60°. The percentage of incident unpolarised light which passes through the system is Show Answer


Q281) Which of the following electromagnetic waves have minimum frequency Show Answer


Q282) In the propagation of light waves, the angle between the direction of vibration and plane of polarization is Show Answer


Q283) Consider Fraunhofer diffraction pattern obtained with a single slit at normal incidence. At the angular position of first diffraction minimum, the phase difference between the wavelets from the opposite edges of the slit is Show Answer


Q284) For skywave propagation of a 10 MHz signal, what should be the maximum electron density in ionosphere Show Answer


Q285) In Fresnel diffraction, if the distance between the disc and the screen is decreased, the intensity of central bright spot will Show Answer


Q286) All components of the electromagnetic spectrum in vacuum have the same Show Answer


Q287) A beam of natural light falls on a system of 5 polaroids, which are arranged in succession such that the pass axis of each polaroid is turned through 60° with respect to the preceding one. The fraction of the incident light intensity that passes through the system is Show Answer


Q288) In which one of the following regions of the electromagnetic spectrum will the vibrational motion of molecules give rise to absorption Show Answer


Q289) If a star is moving towards the earth, then the lines are shifted towards Show Answer


Q290) Light is an electromagnetic wave. Its speed in vacuum is given by the expression Show Answer


Q291) If white light is used in Young’s double slit experiment Show Answer


Q292) In the Young’s double slit experiment, if the phase difference between the two waves interfering at a point is ϕ, the intensity at that point can be expressed by the expression Show Answer


Q293) Which of the following phenomenon exhibits particle’s nature of light? Show Answer


Q294) Due to Doppler’s effect, the shift in wavelength observed is 0.1Å for a star producing wavelength 6000Å. Velocity of recession of the star will be Show Answer


Q295) In a double slit experiment, 5th dark fringe is formed opposite to one the slits. The wavelength of light is Show Answer


Q296) According to Newton’s corpuscular theory, the speed of light is Show Answer


Q297) The rectilinear propagation of light in a medium is due to Show Answer


Q298) In case of linearly polarized light, the magnitude of the electric field vector Show Answer


Q299) The electric and the magnetic field, associated with an e.m. wave propagating along the +z-axis, can be represented by Show Answer


Q300) The electromagnetic waves do not transport Show Answer


Q301) A ray of light is incident on the surface of a glass plate at an angle of incidence equal to Brewster’s angle ϕ. If μ represents the refractive index of glass with respect to air, then the angle between reflected and refracted rays is Show Answer


Q302) If separation between screen and source is increased by 2%, what would be the effect on the intensity Show Answer


Q303) Microwaves from a transmitter are directed normally towards a plane reflector. A detector moves along the normal to the reflector. Between positions of 14 successive maxima, the detector travels a distance of 0.14 m. The frequency of transmitter is Show Answer


Q304) In an apparatus, the electric field was found to oscillate with an amplitude of 18 V/m. The magnitude of the oscillating magnetic field will be Show Answer


Q305) The width of the diffraction band varies Show Answer


Q306) Two non-coherent sources emit light beams of intensities I and 4I . The maximum and minimum intensities in the resulting beam are Show Answer


Q307) Two waves of equal amplitude and frequency interfere each other. The ratio of intensity when the two waves arrive in phase to that when they arrive 90° out of phase is Show Answer


Q308) In Young’s experiment, the third bright band for light of wavelength 6000 Å coincides with the fourth bright band for another source of light in the same arrangement. Then the wavelength of second source is Show Answer


Q309) Air has refractive index 1.003, the thickness of air column, which will have one more wave length of yellow light (6000 Å) than in the same thickness of vacuum is Show Answer


Q310) The phenomenon of interference is shown by Show Answer


Q311) In a Young’s double-slit experiment, constructive interference is produced at a certain point P. The intensities of light at P due to the individual sources are 4 and 9 units. The resultant intensity at point P will be Show Answer


Q312) Illumination of the sun at noon is maximum because Show Answer


Q313) The ratio of intensities of two waves is 9:1. They are producing interference. The ratio of maximum and minimum intensities will be Show Answer


Q314) If white light is used in a biprism experiment then Show Answer


Q315) What should be refractive index of a transparent medium to be invisible in vacuum? Show Answer


Q316) In a YDSE bi-chromatic light of wavelengths 400 nm and 560 nm are used. The distance between the slits is 0.1 mm and the distance between the plane of the slits and the screen is 1 m. The minimum distance between two successive regions of complete darkness is Show Answer


Q317) Which if the following phenomena is not common to sound and light waves? Show Answer


Q318) The range of wavelength of the visible light is Show Answer


Q319) The wave theory of light, in its original form, was first postulated by Show Answer


Q320) Two beams of light will not give rise to an interference pattern, if Show Answer


Q321) The angle of incidence of light is equal to Brewster’s angle, then
A. Reflected ray is perpendicular to refracted ray
B. Refracted ray is parallel to reflected ray
C. Reflected light is polarized having its electric vector in the plane of incidence
D. Refracted light is polarized
Show Answer


Q322) The Fraunhofer diffraction pattern of a single slit is formed in the focal plane of a lens of focal length 1 m. The width of slit is 0.3 mm. If third minimum is formed at a distance of 5 mm from central maximum, then wavelength of light will be Show Answer


Q323) Light of wavelength 6000 Å is incident on a single slit. The first minimum of the diffraction pattern is obtained at 4 mm from the centre. The screen is at a distance of 2 m from the slit. The slit width will be Show Answer


Q324) Which statement is correct for a zone plate and a lens Show Answer


Q325) Red light is generally used to observe diffraction pattern from single slit. If blue light is used instead of red light, then diffraction pattern Show Answer


Q326) In Young’s double slit experiment, the spacing between the slits is d and wavelength of light used is 6000Å. If the angular width of a fringe formed on a distance screen is 1°, then value of d is Show Answer


Q327) What is the minimum thickness of a thin film required for constructive interference in the reflected light from it?
Given, the refractive index of the film = 1.5
Wavelength of the light incident on the film =60nm
Show Answer


Q328) In Young’s double slit experiment, 12 fringes are obtained to be formed in a certain segment of the screen when light of wavelength 600 mm is used. If the wavelength of light is changed to 400 mm, number of fringes observed in the same segment of the screen is given by Show Answer


Q329) A beam of light of wavelength 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between the first dark fringes on either side of the central bright fringe is Show Answer


Q330) In the spectrum of light of a luminous heavenly body the wavelength of a spectral line is measured to be 4747Å while actual wavelength of the line is 4700Å. The relative velocity of the heavenly body with Show Answer


Q331) Maximum diffraction takes place in a given slit for Show Answer


Q332) Which of the following diagrams represent the variation of electric field vector with time for a cirularly polarized light? Show Answer


Q333) In Young’s double slit experiment, slit separation is 0.6 mm and the separation between slit and screen is 1.2 m. The angular width is (the wavelength of light used is 4800 Å Show Answer


Q334) The coherent formula for fringe visibility is Show Answer


Q335) The ratio of the intensity at the centre of a bright fringe to the intensity at a point one-quarter of the distance between two fringe from the centre is Show Answer


Q336) The electromagnetic theory of light failed to explain Show Answer


Q337) In a Young’s double slit experiment, the slit separation is 1 mm and the screen is 1 m from the slit. For a monochromatic light of wavelength 500 nm, the distance of 3rd minima from the central maxima is Show Answer


Q338) An electromagnetic wave travels along z-axis. Which of the following pairs of space and time varying fields would generate such a wave Show Answer


Q339) In double slit experiment, for light of which colour the fringe width will be minimum Show Answer


Q340) The ratio of intensities of successive maxima in the diffraction pattern due to the single slit is Show Answer


Q341) If the total electromagnetic energy falling on a surface is U, then the total momentum delivered (for complete absorption) is Show Answer


Q342) In Young’s double slit experiment, the fringes are displaced by a distance x when a glass plate of one refractive index 1.5 is introduced in the path of one of the beams. When this plate in replaced by another plate of the same thickness, the shift of fringes is (3/2)x. The refractive index of the second plate is Show Answer


Q343) Light of wavelength λ is incident on a slit of widthd. The resulting diffraction pattern is observed on a screen at a distanceD. The linear width of the principal maximum is equal to the width of the slit, if D equals Show Answer


Q344) The maximum number of possible interference maxima for slit-separation equal to twice the wavelength in Young’s double-slit experiment is Show Answer


Q345) The main difference between the phenomena of interference and diffraction is that Show Answer


Q346) In single slit diffraction pattern Show Answer


Q347) A parallel beam of fast moving electrons is incident normally on a narrow slit. A screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statement is correct? Show Answer


Q348) Light is incident on a glass surface at polarizing angle of 57.5°. Then the angle between the incident ray and the refracted ray is Show Answer


Q349) A beam of light consisting of two wavelengths 650 nm and 520 nm is used to illuminate the slit of a Young’s double slit experiment. Then the order of the bright fringe of the longer wavelength that coincide with a bright fringe of the shorter wavelength at the least distance from the central maximum is Show Answer


Q350) Light is incident normally on a diffraction grating through which the first order diffraction is seen at 32°. The second order diffraction will be seen at Show Answer


Q351) How fast a person should drive his car so that the red signal of light appears green?
(Wavelength for red colour =6200Å and wavelength for green colour =5400Å)
Show Answer


Q352) An optically active compound Show Answer


Q353) A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 10m from the lamp will be Show Answer


Q354) For a wave propagating in a medium, identify the property that is independent of the others Show Answer


Q355) In Fraunhofer diffraction experiment, L is the distance between screen and the obstacle, b is the size of obstacle and λ is wavelength of incident light. The general condition for the applicability of Fraunhofer diffraction is Show Answer


Q356) If the shift of wavelength of light emitted by a star is towards violet, then this shows that star is Show Answer


Q357) In the phenomenon of diffraction of light, when blue light is used in the experiment instead of red light, then Show Answer


Q358) The electromagnetic wave having the shortest wavelength is Show Answer


Q359) In a double slit arrangement fringes are produced using light of wavelength 4800 Å. One slit is covered by a thin plate of glass of refractive index 1.4 and the other with another glass plate of same thickness but of refractive index 1.7. By doing so the central bright shifts to original fifth bright fringe from centre. Thickness of glass plate is Show Answer


Q360) A very thin film that reflects white light appears Show Answer


Q361) The diffraction effect can be observed in
++ Show Answer


Q362) Which of the following is a dich roic crystal? Show Answer


Q363) A parallel beam of fast moving electrons is incident normally on a narrow slit. A screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statement is correct Show Answer


Q364) In a double slit experiment, the distance between slits is increased 10 times whereas their distance from screen is halved, then what is the fringe width? Show Answer


Q365) In Young’s double slit experiment intensity at a point is (1/4) of the maximum intensity. Angular position of this point is Show Answer


Q366) Approximate height of ozone layer above the ground is Show Answer


Q367) Light of wavelength 500nm is used to form interference pattern in Young’s double slit experiment. A uniform glass plate of refractive index 1.5 and thickness 0.1nm is introduced in the path of one of the interfering beams. The number of fringes which will shift the cross wire due to this is Show Answer


Q368) The ozone layer absorbs Show Answer


Q369) The wavefront of distant source of unknown shape is approximately Show Answer


Q370) Which of the following are not electromagnetic waves Show Answer


Q371) Plane microwaves are incident on a long slit having a width of 5 cm. The wavelength of the microwaves if the first minimum is formed at 30° is Show Answer


Q372) In the phenomenon of interference, energy is Show Answer


Q373) In Huygen’s wave theory, the locus of all points in the same state of vibration is called Show Answer


Q374) The angle of polarization for any medium is 60°, what will be critical angle for this Show Answer


Q375) Through quantum theory of light we can explain a number of phenomena observed with light, it is necessary to retain the wave nature of light to explain the phenomenon of Show Answer


Q376) Huygens wave theory allows us to know Show Answer


Q377) A polarizer is used to Show Answer


Q378) How will the diffraction pattern of single slit change when yellow light us replaced by blue light? The fringe will be Show Answer


Q379) In Young’s double slit experiment intensity at a point is (1/4) of the maximum intensity. Angular position of this point is Show Answer


Q380) The size of an obstacle in order to observe diffraction of light must be Show Answer


Q381) In the Young’s double slit experiment, the interference pattern is found to have an intensity ratio between bright and dark fringes as 9. This implies that Show Answer


Q382) A screen is placed 50cm from a single slit, which is illuminated with 6000Å light. If distance between the first and third minima in the diffraction pattern is 3mm, the width of the slit is Show Answer


Q383) Assuming that universe is expanding, if the spectrum of light coming from a star which is going away from earth is tested, then in the wavelength of light Show Answer


Q384) In Young’s double slit experiment, when two light waves form third minimum, they have Show Answer


Q385) Which of the following generates a plane wave front? Show Answer


Q386) Electromagnetic waves are transverse in nature is evident by Show Answer


Q387) Pick out the longest wavelength from the following types of radiations Show Answer


Q388) Which of the following radiations has the least wavelength Show Answer


Q389) A Young’s double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen is Show Answer


Q390) Which of the following has/have zero average value in a plane electromagnetic wave Show Answer


Q391) In Young’s double slit experiment if monochromatic light used is replaced by white light, then Show Answer


Q392) In Young’s double slit experiment, the interference pattern is found to have an intensity ratio between bright and dark fringes is 9, this implies that Show Answer


Q393) In order to see diffraction the thickness of the film is Show Answer


Q394) The 6563 Å line emitted by hydrogen atom in a star is found to be red shifted by 5 Å. The speed with which the star is receding from the earth is Show Answer


Q395) According to Maxwell’s hypothesis, a changing electric field gives rise to Show Answer


Q396) Which of the following statements is true, when spherical waves fall on a plane refracting surface, separating two media Show Answer


Q397) Doppler’s effect in sound in addition to relative velocity between source and observer, also depends while source and observer or both are moving. Doppler effect in light depends only on the relative velocity of source and observer. The reason of this is Show Answer


Q398) In Young’s double slit experiment, the length if band is 1 mm. The ring width is 1.021 mm. The number of fringe is Show Answer


Q399) Electromagnetic radiation of highest frequency is Show Answer


Q400) In a double slit interference experiment, the distance between the slits is 0.05 cm and screen is 2 m away from the slits. The wavelength of light is 6000Å. The distance between the fringe is Show Answer


Q401) In a Fresnel biprism experiment, the two positions of lens give separation between the slits as 16 cm and 9 cm, respectively. What is the actual distance of separation? Show Answer


Q402) The condition for diffraction of m th order minima is Show Answer


Q403) A plane electromagnetic wave is incident on a material surface. If the wave delivers momentum p and energy E, then Show Answer


Q404) A parallel beam of light of wavelength 6000Å gets diffracted by a single silt of width 0.3 mm. The angular position of the first minima of diffracted light is Show Answer


Q405) Wave which cannot travel in vacuum is Show Answer


Q406) Which radiation in sunlight, causes heating effect Show Answer


Q407) A thin film of soap solution (n=1.4) lies on the top of a glass plate (n=1.5). When visible light is incident almost normal to the plate, two adjacent reflection maxima are observed at two wavelengths 400 and 630 nm. The minimum thickness of the soap solution is Show Answer


Q408) Radio waves and visible light in vacuum have Show Answer


Q409) A single slit is located effectively at infinity in front of a lens of focal length 1 m and it is illuminated normally with light of wavelength 600 nm. The first minima on either side of central maximum are separated by 4 mm. Width of the slit is …… Show Answer


Q410) A parallel plate capacitor with plate area A and separation between the plates d, is charged by a constant current i, consider a plane surface of area A/2 parallel to the plates and drawn symmetrically between the plates, the displacement current through this area, will be Show Answer


Q411) The coherent curve between fringe width β and distance between the slits (d)in figure is Show Answer


Q412) The intensity ratio of two coherent sources of light is p. They are interfering in some region and produce interference pattern. Then the fringe visibility is Show Answer


Q413) Colours in thin films are due to Show Answer


Q414) In Young’s double slit experiment, the two slit act as coherent sources if equal amplitude A and wavelengthλ. In another experiment with the same setup, the two slits are sources of equal amplitude A and wavelength λ but are incoherent. The ratio of the intensity of light at the mid-point of the screen in the first case to that in the second case is Show Answer


Q415) Consider Fraunhoffer diffraction pattern obtained with a single slit at normal incidence. At the angular position of first diffraction minimum, the phase difference between the wavelets from the opposite edges of the slit is Show Answer


Q416) What is the minimum thickness of a thin film required for constructive interference in the reflected light from it?
Given, the refractive index of the film = 1.5, wavelength of the light incident on the film = 600 nm

Show Answer


Q417) To observe diffraction, the size of an aperture Show Answer


Q418) When two coherent monochromatic light beams of intensities I and 4I are superimposed. What are the maximum and minimum possible intensities in the resulting beams? Show Answer


Q419) Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R Assertion A The phase difference of two light waves change if they travel through different media having same thickness, but different indices of refraction. Reason R The wavelengths of waves are different in different media.
In the light of the above statements, choose the most appropriate answer from the options given below
Show Answer


Q420) A travelling wave is described by the equation y(x,t)=[0.05sin(8x-4t)]m .
The velocity of the wave is (all the quantities are in SI unit
Show Answer


Q421) Which of the following equations represents a
travelling wave?
Show Answer


Q422) For a transverse wave travelling along a straight line, the distance between two peaks (crests) is 5 m, while -the distance between one crest and one trough is 1.5 m. The possible wavelengths (in metre) of the Waves are Show Answer


Q423) A string of length 1 m and mass 5 g is fixed at both ends. The tension in the string is 8.0 N. The string is set into vibration using an external vibrator of frequency 100 Hz. The separation between successive nodes on the string is close to Show Answer


Q424) In a transverse wave, the distance between a crest and neighbouring trough at the same instant is 4.0 cm and the distance between a crest and trough at the same place is 1.0 cm. The next crest appears at the ziz same place after a time interval of 0.4 s. The maximum speed of the vibrating particles in the medium is Show Answer


Q425) A sound absorber attenuates the sound level by 20 db. The intensity decreases by a factor of Show Answer


Q426) The intensity of gamma radiation from a given source is I. On passing through 36 mm of lead, it is reduced to I/8. The thickness of lead, which will reduce the intensity to I/2 will be Show Answer


Q427) The difference in the number of waves when yellow light propagates through air and vacuum columns of the same thickness is one. The thickness of the air column is ......mm
[Take, refractive index of air = 1.0003, wavelength of yellow light in vacuum = 6000 Å] Show Answer


Q428) A tuning fork A of unknown frequency produces 5 beats/s with a fork of known frequency 340 Hz. When fork A is filled, the beat frequency decreases to 2 beats/s. What is the frequency of fork A?
Show Answer


Q429) A student is performing the experiment of resonance column. The diameter of the column tube is 6 cm. The frequency of the tuning fork is 504 Hz. Speed of the sound at the given temperature is 336 m/s. The zero of the metre scale coincides with the top end of the resonance column tube. The reading of the water level in the column when the first resonance occurs is Show Answer


Q430) In a resonance tube experiment, when the tube is filled with water up to a height of 17.0 cm from bottom, it resonates with a given tuning fork. When the water level is raised, the next resonance with the gian same tuning fork occurs at a height of 24.5 cm. If the velocity of sound in air is 330 m/s, the tuning fork [ETOC frequency is Show Answer


Q431) A string 2.0 m long and fixed at its ends is driven by (-a 240 Hz vibrator. The string vibrates in its third harmonic mode. The speed of the wave and its fundamental frequency is Show Answer


Q432) The correct figure that shows schematically, the wave pattern produced by superposition of two waves of frequencies 9 Hz and 11 Hz, is Show Answer


Q433) A resonance tube is old and has jagged end. It is still used in the laboratory to determine velocity of sound in air. A tuning fork of frequency 512 Hz produces first resonance when the tube is filled with water to a mark 11 cm below a reference mark. near the open end of the tube. The experiment is repeated with another fork of frequency 256 Hz which produces first resonance when water reaches a mark 27 cm mbelow the reference mark. The velocity of sound in air, obtained in the experiment is close to Show Answer


Q434) A pipe open at both ends has a fundamental frequency f in air. The pipe is dipped vertically in water, so that half of it is in water. The fundamental no frequency of the air column is now Show Answer


Q435) A pipe of length 85 cm is closed from one end. Find the number of possible natural oscillations of air column in the pipe whose frequencies lie below is 1250 Hz. The velocity of sound in air is 340 m/s. Show Answer


Q436) A cylindrical tube open at both ends, has a fundamental frequency f, in air. The tube is dipped big vertically in water so that half of it is in water. The fundamental frequency of the air-column is now Show Answer


Q437) Three sound waves of equal amplitudes have frequencies (v-1), v, (v + 1). They superpose to give beat. The number of beats produced per second will be Show Answer


Q438) While measuring the speed of sound by performing a the first gets resonance column experiment, a student 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


Q439) A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonants) Isin frequencies of 420 Hz and 315 Hz. There are no fotos other resonant frequencies between these two. Then, the lowest resonant frequency for this string is Show Answer


Q440) When two tuning forks (fork 1 and fork 2) are Aa 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, 10 6 beats per second are heard.
If the frequency of fork 1 is 200 Hz, then what will be the original frequency of fork 2?
Show Answer


Q441) A metal wire of linear mass density of 9.8 g/m is stretched with a tension of 10 kg-wt between two rigid supports 1 m apart. The wire passes at its middle ECO point between the poles of a permanent magnet and it vibrates in resonance when carrying an alternating current of frequency n. The frequency n of the alternating source is
Show Answer


Q442) 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 per second when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was
Show Answer


Q443) A guitar string of length 90 cm vibrates with a fundamental frequency of 120 Hz. The length of the string producing a fundamental frequency of 180 Hz will be ....... cm. Show Answer


Q444) A wire of length of 30 cm, stretched between rigid supports, has it's nth and (n + 1)th harmonics at 400 Hz and 450 Hz, respectively. If tension in the string is 2700 N, its linear mass density is ....
kg/m. Show Answer


Q445) A set of 20 tuning forks is arranged in a series of increasing frequencies. If each fork gives 4 beats with respect to the preceding fork and the frequency of the last fork is twice the frequency of the first, then the frequency of last fork is ...... Hz. Show Answer


Q446) A one metre long (both ends open) organ pipe is kept in a gas that has double the density of air at STP. Assuming the speed of sound in air at STP is 300 m/s, the frequency difference between the fundamental and second harmonic of this pipe is. .... Hz Show Answer


Q447) A person observes two moving trains, A reaching the station and B leaving the station with equal speed of 30 m/s. If both trains emit sounds with frequency 300 Hz, (Speed of sound: 330 m/s) approximate will be person difference of frequencies heard by the person will be Show Answer


Q448) An observer moves towards a stationary source of sound with a velocity equal to one-fifth of the mo velocity of sound. The percentage change in the frequency will be Show Answer


Q449) A driver in a car, approaching a vertical wall notices that the frequency of his car horn, has changed from 440 Hz to 480 Hz, when it gets reflected from the wall. If the speed of sound in air is 345 m/s, then the speed of the car is Show Answer


Q450) amath
A source of sound S is moving with a velocity of
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? (Take, velocity of sound in air is 350 m/s) Show Answer


Q451) A musician using an open flute of length 50 cm produces second harmonic sound waves. A person runs towards the musician from another end of a hall at a speed of 10 km/h. If the wave speed is 330 m/s, the frequency heard by the running person shall be close to Show Answer


Q452) Two sitar strings, A and B, playing the note 'Dha' are slightly out of tune and produce beats and frequency 5 Hz. The tension of the string B is slightly increased and the beat frequency is found to decrease by 3 Hz. If the frequency of A is 425 Hz, the original frequency of B is Show Answer


Q453) A toy-car, blowing its horn, is moving with a steady speed of 5 m/s, away from a wall. An observer, 5 beats towards whom the toy car is moving, is able to hear per second. If the velocity of sound in air is 340 m/s, the frequency of the horn of the toy car is Show Answer


Q454) 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


Q455) A person driving car at a constant speed of 15 m/s is approaching a vertical wall. The person notices a change of 40 Hz in the frequency of his car's horn upon reflection from the wall. The frequency of horn is ........ Hz.
(Given, Speed of sound: 330 m/s) Show Answer


Q456) A wire of length 30 cm, stretched between rigid supports, has it's nth and (n + 1)th harmonics at 400 Hz and 450 Hz, respectively.If tension in the string is 2700 N, it's linear mass density is kg/m. Show Answer


Q457) The frequency of echo will be …. blowing a whistle of frequency 320 Hz is moving with a velocity of 36 km/h towards a hill from which an echo is heard by the train driver. (Velocity of sound in air is 330 m/s). Show Answer


Q458) When a car is approaching the observer, the frequency of horn is 100 Hz. After passing the observer, it is 50 Hz. If the observer moves with the car, the frequency will be
x/3 Hz where x = ....
Show Answer


Q459) Two cars are approaching each other at an equal o speed of 7.2 km/h. When they see each other, both blow horns having frequency of 676 Hz. The beat frequency heard by each driver will be .... Hz. [Velocity of sound in air is 340 m/s.] Show Answer


Q460) Two cars X and Y are approaching each other with velocities 36 km/h and 72 km/h respectively. The frequency of a whistle sound as emitted by a passenger in car X, heard by the passenger in car Y is 1320 Hz. If the velocity of sound in air is 340 m/s, the actual frequency of the whistle sound produced is ..... Hz. Show Answer


Q461) A source and a detector move away from each other in absence of wind with a speed of 20 m/s with respect to the ground. If the detector detects a frequency of 1800 Hz of the sound coming from the source, then the original frequency of source lib considering speed of sound in air 340 m/s will be .... Hz. Show Answer


Q462) The width of fringe is 2 mm on the screen in a double slits experiment for the light of wavelength of 400 nm. The width of the fringe for the light of wavelength 600 nm will be Show Answer


Q463) In Young's double slits experiment, the position of 5th bright fringe from the central maximum is 5 cm. The distance between slits and screen is 1 m and wavelength of used monochromatic light is 600 nm. The separation between the slits is Show Answer


Q464) In Young's double slit experiment, the fringe width is 12 mm. If the entire arrangement is placed in water of refractive index 4/3, then the fringe width becomes (in mm) Show Answer


Q465) Using Young's double slit experiment, a monochromatic light of wavelength 5000 Å produces fringes of fringe width 0.5 mm. If another monochromatic light of wavelength 6000 Å is used and the separation between the slits is doubled, then the new fringe width will be Show Answer


Q466) Two light beams of intensities in the ratio of 9: 4 are allowed to interfere. The ratio of the intensity of maxima and minima will be
Show Answer


Q467) For a specific wavelength 670 nm of light coming from a galaxy moving with velocity v, the observed wavelength is 670.7 nm. The value of vis: Show Answer


Q468) The two light beams having intensities I and 91 interfere to produce a fringe pattern on a screen. The phase difference between the beams is π / 2 at point Р and л at point Q. Then the difference between the resultant intensities at P and Q will be Show Answer


Q469) In Young's double slit experiment the two slits are separated by 2 mm and the screen is placed one meter away. When a light of wavelength 500 nm is used, the fringe separation will be Show Answer


Q470) In Young's double slit experiment, if the source of light changes from orange to blue, then Show Answer


Q471) In Young's double slit arrangement, slits are separated by a gap of 0.5 mm, and the screen is d placed at a distance of 0.5 m from them. The() distance between the first and the third bright fringe formed when the slits are illuminated by a monochromatic light of 5890 Å is Show Answer


Q472) In Young's double slit experiment, two slits are separated by 2 mm and the screen is placed one metre away. When a light of wavelength 500 nm is used, the fringe separation will be Show Answer


Q473) If the source of light used in a Young's double slit experiment is changed from red to violet, then Show Answer


Q474) In Young's double slit experiment, the width of one of the slit is three times the other slit. The amplitude of the light coming from a slit is proportional to the slit-width. Find the ratio of the maximum to the minimum intensity in the interference pattern. Show Answer


Q475) In Young's double slit experiment, 16 fringes are observed in a certain segment of the screen when light of wavelength 700 nm is used. If the wavelength of -light is changed to 400 nm, the number of fringes observed in the same segment of the screen would be Show Answer


Q476) In Young's double slit experiment, light of 500 nm is used to produce an interference pattern. When the distance between the slits is 0.05 mm, the angular width (in degree) of the fringes formed on the distance screen is close to Show Answer


Q477) In Young's double slit experiment, the separation between the slits is 0.15 mm. In the experiment, a source of light of wavelength 589 nm is used and the interference pattern is observed on a screen kept 1.5 m away. The separation between the successive U-bright fringes on the screen is Show Answer


Q478) In Young's double slit experiment, the ratio of the slit's width is 4: 1. The ratio of the intensity of maxima to minima, close to the central fringe on the screen, will be Show Answer


Q479) In double slit experiment, when a thin film of thickness t having refractive index u is introduced in μ front of one of the slits, the maximum at the centre of the fringe pattern shifts by one fringe width. The value of t is is the wavelength of the light used) Show Answer


Q480) Two coherent sources produce waves of different intensities which interfere. After interference, the ratio of the maximum intensity to the minimum intensity is 16. The intensity of the waves are in the ratio Show Answer


Q481) In Young's double slit experiment, the path difference at a certain point on the screen between two interfering waves is 1/8th of wavelength. The ratio of the intensity at this point to that at the centre of a bright fringe is close to Show Answer


Q482) In Young's double slit experiment, slits are separated
by 0.5 mm and the screen is placed 150 cm away. A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes on the screen. The least distance from the common central maximum to the point where the bright fringes due to both the wavelengths coincide, is
Show Answer


Q483) On a hot summer night, the refractive index of air is smallest near the ground and increases with height from the ground. When a light beam is directed horizontally, the Huygens principle leads us to conclude that as it travels, the light beam Show Answer


Q484) Two monochromatic light beams of intensity 16 and 9 units are interfering. The ratio of intensities of bright and dark parts of the resultant pattern is: Show Answer


Q485) n identical waves each of intensity I interfere with each other. The ratio of maximum intensities if the interference is (i) coherent and (ii) incoherent is Show Answer


Q486) The initial shape of the wavefront of the beam is Show Answer


Q487) A mixture of light, consisting of wavelength 590 nm and an unknown wavelength, illuminates Young's double slit and gives rise to two overlapping interference patterns on the screen. The central maximum of both lights coincide. Further, it is nb observed that the third bright fringe of known light coincides with the 4th bright fringe of the unknown
or light. From this data, the wavelength of the unknown light is
Show Answer


Q488) A Young's double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen is Show Answer


Q489) The maximum number of possible interference maxima for slit-separation equal to twice the rewavelength in Young's double-slit experiment, is Show Answer


Q490) Two light waves of wavelengths 800 and 600 nm are used in Young's double slit experiment to obtain interference fringes on a screen placed 7 m away from plane of slits. If the two slits are separated by 0.35 mm, then shortest distance from the central bright maximum to the point where the bright fringes of the two wavelength coincide will be .... mm Show Answer


Q491) In Young's double slit experiment, a laser light of 560 nm produces an interference pattern with consecutive bright fringes separation of 7.2 mm. Los Now, another light is used to produce an interference pattern with consecutive bright fringes separation of 81 mm. The wavelength of second light is ..... nm. Show Answer


Q492) In Young's double slit experiment the two slits are 0.6 mm distance apart. Interference pattern is observed on a screen at a distance 80 cm from the slits. The first dark fringe is observed on the screen directly opposite to one of the slits. The wavelength of light will be...... nm. Show Answer


Q493) The width of one of the two slits in a Young's double 1216 slit experiment is three times the other slit. If the amplitude of the light coming from a slit is proportional to the slit-width, the ratio of minimum to maximum intensity in the interference pattern is x:4 where x is ....
Show Answer


Q494) White light is passed through a double slit and interference is observed on a screen 1.5 m away. The separation between the slits is 0.3 mm. The first violet and red fringes are formed 2.0 mm and 3.5 mm away from the central white fringes. The difference in wavelengths of red and violet light is ..... nm. Show Answer


Q495) A fringe width of 6 mm was produced for two slits separated by 1 mm. The screen is placed 10 m away. The wavelength of light used is x nm. The value of x to the nearest integer is ..... Show Answer


Q496) With what speed should a galaxy move outward with respect to Earth, so that the sodium-D line at wavelength 5890 Å is observed at 5896 Å? Show Answer


Q497) Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter 0.1μm. If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that Show Answer


Q498) Diameter of the objective lens of a telescope is 250 cm. For light of wavelength 600 nm coming from a distant object, the limit of resolution of the telescope is close to Show Answer


Q499) The value of numerical aperture of the objective lens a microscope is 1.25. If light of wavelength 5000Å is used, the minimum separation between two points, to be seen as distinct, will be Show Answer


Q500) Calculate the limit of resolution of a telescope objective having a diameter of 200 cm, if it has to detect light of wavelength 500 nm coming from a star. Show Answer


Q501) In a double-slit experiment, green light (5303 Å) falls on a double slit having a separation of 19.44 μm and a width of 4.05 μm. The number of bright fringes between the first and the second diffraction minima is Show Answer


Q502) The angular width of the central maximum in a single slit diffraction pattern is 60°. The width of the slit is 1 μm. The slit is illuminated by T monochromatic plane waves. If another slit of same width is made near it, Young's fringes can be observed on a screen placed at a distance 50 cm from the slits. If the observed fringe width is 1 cm, what is slit separation distance? (i.e. distance between the centres of each slit.) Show Answer


Q503) A single slit of width b is illuminated by a coherent monochromatic light of wavelength λ. If the second and fourth minima in the diffraction pattern at a distance 1 m from the slit are at 3 cm and 6 cm respectively from the central maximum, what is the width of the central maximum? (i.e. distance between first minimum on either side of the central maximum) Show Answer


Q504) Assuming human pupil to have a radius of 0.25 cm and a comfortable viewing distance of 25 cm, the minimum separation between two objects that human eye can resolve at 500 nm wavelength is Show Answer


Q505) Two point white dots are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm. Approximately, what is the maximum distance at which these dots can be resolved by the eye? [Take wavelength of light = 500 nm] Show Answer