Practice Test


1) 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


2) 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


3) Bright coiours exhibited by spider's web, exposed to sunlight, are due to


4) 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


5) 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


6) For the constructive interference the path difference between the two interfering waves must be equal to


7) 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


8) If white light is used in Young's double slit experiment


9) to demonstrate the phenomenon of interference, we require two sources which emit radiation


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


11) 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


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


13) Young's experiment establishes that


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


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


16) 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


17) The power transmitted through B is


18) The phase difference introduced by the film is


19) The power in watt received at the focal point F of the lens is


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


21) 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


22) 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


23) Find the wavelength of parallel beam in liquid


24) Calculate the fringe width


25) 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


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


27) 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 ?


28) 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


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


30) The shape fringe patterns in YDSE is


31) If we replace the monochromatic source in YDSE by white light, then


32) 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 )


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


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


35) 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.


36) 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


37) 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


38) Pick out the correct statements


39) 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


40) The penetration of light into the region of geometrical shadow is called


41) To observe diffraction, the size of an obstacle


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


43) 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 )


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


45) The wavelength of light can be experimentally found using


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


47) The frequency of light can be experimentally found using


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


49) 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


50) 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


51) Only transverse waves undergo


52) If a wave can be polarized, it must be


53) 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


54) Waves that cannot be polarized are


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


56) The separation between the first order minima on the screen is


57) The width of the central maximum is


58) Polaroid sheets are often used for making sun glasses. This is because polaroid glasses


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


60) The correct expression relating polarising angle and refractive index is


61) The experimental proof that light is a transverse wave may be obtained through


62) 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


63) 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


64) 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


65) 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


66) At the Brewster angle of incidence, the reflected light is polarised.


67) The Brewster angle is


68) At the Brewstar's angle


69) By corpuscular theory of light, the phenomenon which can be explained is


70) According to corpuscular theory of light, the different colours of light are due to


71) Huygen's conception of secondary waves


72) The idea of the quantum nature of light has emerged in an attempt to explain


73) Two coherent sources of light can be obtained by


74) By Huygen's wave theory of light, we cannot explain the phenomenon of


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


76) Light appears to travel in straight lines since


77) The idea of secondary wavelets for the propagation of a wave was first given by


78) By a monochromatic wave, we mean


79) The similarity between the sound waves and light waves is


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


81) A wave can transmit ........... from one place to another


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


83) Wave nature of light follows because


84) If L is the coherence length and c the velocity of light, the coherent time is


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


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


87) Two sources of waves are called coherent if


88) Soap bubble appears coloured due to the phenomenon of


89) 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


90) Evidence for the wave nature of light cannot be obtained from


91) Two light sources are said to be coherent if they are obtained from


92) Wavelength of light of frequency 100 Hz


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


94) Wavefront means


95) Wavefront of a wave has direction with wave motion


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


97) 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


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


99) For the sustained interference of light, the necessary condition is that the two sources should


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


101) Which of the following is conserved when light waves interfere


102) Intensity of light depends upon


103) Ray diverging from a point source from a wave front that is


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


105) Newton postulated his corpuscular theory on the basis of


106) The dual nature of light is exhibited by


107) Coherent sources are those sources for which


108) Wave nature of light is verified by


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


110) Laser beams are used to measure long distance because


111) 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


112) The frequency of light ray having the wavelength 3000Å is


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


114) Huygen's principle of secondary wavelets may be used to


115) What is the path difference of destructive interference


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


117) As a result of interference of two coherent sources of light, energy is


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


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


120) Huygen wave theory allows us to know


121) The wave theory of light was given by


122) Which of the following phenomena can explain quantum nature of light


123) Which of the following is not a property of light


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


125) Select the right option in the following


126) Two waves of intensity I undergo Interference. The maximum intensity obtained is


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


128) In the interference pattern, energy is


129) 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


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


131) 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


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


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


134) 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


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


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


137) 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


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


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


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


141) 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


142) 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


143) In an interference experiment, the spacing between successive maxima or minima is


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


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


146) 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


147) 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


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


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


150) The fringe width in Young's double slit experiment increases when


151) 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


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


153) 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


154) 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


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


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


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


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


159) 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


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


161) 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


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


163) 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


164) 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


165) 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


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


167) 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


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


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


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


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


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


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


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


175) In which of the following is the interference due to the division of wave front


176) The bending of beam of light around corners of obstacles is called


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


178) 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


179) 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


180) Conditions of diffraction is


181) The radius r of half period zone is proportional to


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


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


184) 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


185) A polariser is used to


186) Light waves can be polarised as they are


187) Which of following can not be polarised


188) Out of the following statements which is not correct


189) The transverse nature of light is shown by


190) Refractive index of material is equal to tangent of polarising angle. It is called


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


192) The phenomenon of polarization of light indicates that


193) 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


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


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


196) 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?


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


198) 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


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


200) Which of the following cannot be polarized?


201) 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


202) The wavelength of the matter waves is independent of


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


204) 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


205) In the diffraction pattern of a single slit


206) Two light sources are said to be coherent if they are obtained from


207) 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?


208) 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


209) If Young’s double slit experiment, is performed in water


210) Which of the following shows green house effect


211) 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


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


213) In a diffraction pattern by a wire, on increasing diameter of wire, fringe width


214) 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


215) Which one of the following property of light does not support wave theory of light?


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


217) 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


218) 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


219) 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


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


221) 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


222) 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


223) 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


224) Through which character we can distinguish the light waves from sound waves


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


226) 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


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


228) The electromagnetic waves travel with a velocity


229) 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


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


231) Which of the following statements indicates that light waves are transverse


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


233) 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


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


235) 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


236) 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


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


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


239) Out of the following statements which is not correct


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


241) 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


242) 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


243) 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


244) The oscillating electric and magnetic vectors of an electromagnetic wave are oriented along


245) 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


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


247) Which of the following waves have the maximum wavelength


248) 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


249) 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


250) Which of the following phenomena can explain quantum nature of light


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


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


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


254) For the constructive interference the path difference between the two interfering waves must be equal to


255) 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


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


257) 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


258) Interference may be seen using two independent


259) 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


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


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


262) 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


263) 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


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


265) 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


266) What is ozone hole


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


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


269) 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


270) 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


271) The phenomenon which does not take place in sound waves is


272) The speed of electromagnetic wave in vacuum depends upon the source of radiation


273) 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


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


275) 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


276) Which phenomenon best supports the theory that matter has a wave nature?


277) In Young’s double slit interference pattern the fringe width


278) H-polaroid is prepared by


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


280) 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


281) Which of the following electromagnetic waves have minimum frequency


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


283) 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


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


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


286) All components of the electromagnetic spectrum in vacuum have the same


287) 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


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


289) If a star is moving towards the earth, then the lines are shifted towards


290) Light is an electromagnetic wave. Its speed in vacuum is given by the expression


291) If white light is used in Young’s double slit experiment


292) 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


293) Which of the following phenomenon exhibits particle’s nature of light?


294) 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


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


296) According to Newton’s corpuscular theory, the speed of light is


297) The rectilinear propagation of light in a medium is due to


298) In case of linearly polarized light, the magnitude of the electric field vector


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


300) The electromagnetic waves do not transport


301) 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


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


303) 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


304) 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


305) The width of the diffraction band varies


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


307) 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


308) 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


309) 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


310) The phenomenon of interference is shown by


311) 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


312) Illumination of the sun at noon is maximum because


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


314) If white light is used in a biprism experiment then


315) What should be refractive index of a transparent medium to be invisible in vacuum?


316) 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


317) Which if the following phenomena is not common to sound and light waves?


318) The range of wavelength of the visible light is


319) The wave theory of light, in its original form, was first postulated by


320) Two beams of light will not give rise to an interference pattern, if


321) 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


322) 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


323) 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


324) Which statement is correct for a zone plate and a lens


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


326) 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


327) 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


328) 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


329) 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


330) 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


331) Maximum diffraction takes place in a given slit for


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


333) 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


334) The coherent formula for fringe visibility is


335) 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


336) The electromagnetic theory of light failed to explain


337) 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


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


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


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


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


342) 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


343) 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


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


345) The main difference between the phenomena of interference and diffraction is that


346) In single slit diffraction pattern


347) 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?


348) 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


349) 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


350) 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


351) 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)


352) An optically active compound


353) 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


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


355) 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


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


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


358) The electromagnetic wave having the shortest wavelength is


359) 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


360) A very thin film that reflects white light appears


361) The diffraction effect can be observed in
++


362) Which of the following is a dich roic crystal?


363) 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


364) 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?


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


366) Approximate height of ozone layer above the ground is


367) 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


368) The ozone layer absorbs


369) The wavefront of distant source of unknown shape is approximately


370) Which of the following are not electromagnetic waves


371) 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


372) In the phenomenon of interference, energy is


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


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


375) 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


376) Huygens wave theory allows us to know


377) A polarizer is used to


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


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


380) The size of an obstacle in order to observe diffraction of light must be


381) 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


382) 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


383) 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


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


385) Which of the following generates a plane wave front?


386) Electromagnetic waves are transverse in nature is evident by


387) Pick out the longest wavelength from the following types of radiations


388) Which of the following radiations has the least wavelength


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


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


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


392) 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


393) In order to see diffraction the thickness of the film is


394) 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


395) According to Maxwell’s hypothesis, a changing electric field gives rise to


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


397) 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


398) 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


399) Electromagnetic radiation of highest frequency is


400) 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


401) 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?


402) The condition for diffraction of m th order minima is


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


404) 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


405) Wave which cannot travel in vacuum is


406) Which radiation in sunlight, causes heating effect


407) 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


408) Radio waves and visible light in vacuum have


409) 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 ……


410) 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


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


412) 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


413) Colours in thin films are due to


414) 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


415) 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


416) 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


417) To observe diffraction, the size of an aperture


418) 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?