Wave Optics Questions and Answers

17 Young s double slit experment is first performed in air and then in a medium other than air It is found that 8th bright fringe in the medium lies where 5th dark fringe lies in air The refractive index of the medium is nearly 1 1 59 2 1 69 3 1 78 4 1 25 A beam of light from a source L is incident ve is 18

6 The periodic waves of intensities I and 1 pas through a region at the same time in the sam direction The sum of the maximum and minimun intensities is les 2008 2 b 1 a 1 1 11 c IT I d 2 1 1

The Young s double slit experiment is performed with blue and with green light of wavelengths 4360 and 5460A respectively Ifx is the distance of 4th maxima from the central one then 1990 a x blue x green b x blue x green c x blue x green d x blue green 5460 1360

In Young s experiment two coherent sources are placed 0 90 mm apart and fringe are observed one metre away If it produces second dark fringe at a distance of 1 mm from central fringe the wavelength of monochromatic light used would be 1991 1992 a 60 104cm c 10 x 10 5 cm b 10 x 10 cm d 6 x 10 5 cm

53 The intensity at the maximum in a Young s double slit experiment is Io Distance between two slits is d 52 where is the wavelength of light used in the experiment What will be the intensity in front of one of the slits on the screen placed at a distance D 10 d 2016 a In 3 b d Io 4 2

146 A beam of light of 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 first dark fringes on either side of the central bright fringe is 2014 1 a 1 2 cm c 2 4 cm In the Young s double slit experiment the 5 b 1 2mm d 2 4mm

screen in case of D In Young s double slit experiment the distance between the slits and the screen is doubled The separation between the slits is reduced to half As a result the fringe width NEET Kar 2013 a is doubled b is halved c becomes four times

If yellow light emitted by sodium lamp in Young s double slit experiment is replaced by a monochromatic blue light of the same intensity a fringe width will decrease b finge width will increase 1992 c fringe width will remain unchanged d fringes will become less intense

In Young s double slit experiment the fringe width is found to be 0 4 mm If the whole apparatus is immersed in water of refrative index 4 39 without disturbing the geometrical arrangement the new fringe width will be 1990 a 0 30mm b 0 40mm c 0 53 mm d 450 microns

Fraunhofer lines are found in 1 Emission spectrum of the elements present in photosphere 2 The absorption spectrum of the elements present in photosphere 3 The emission spectrum of the elements present chromosphere 4 The absorption spectrum of the elements present in chromosphere

Diameter of human eye lens is 2 mm What will be the minimum distance between two points to resolve them which are situated at a distance of 50 meter from eye The wavelength of light is 5000 A 2 32 m B 4 28 mm C 1 25 cm D 12 48 cm 11

beam of unpolarized light passes through two ideal polarizing filters with different ientations as shown in the figure What is the ratio of the final intensity of the beam to the tial intensity Incident light 40 O O 50 Transmitted light

Light of wavelength 500 nm travelling with a speed of 2 0 108 ms in a certain medium enters another medium of refractive index 5 4 times that of the first medium What are the wavelength and speed in the second medium Wavelength nm 500 nm Y f Wavelength nm A Speed ms 2 0 108 ms qu meng v n sa faccen 400 B 400 C 500 D 625 Speed ms Your Answer 1 6 108 2 5 108 2 5 108 1 6 108 A Correct Answer

A spy satellite moves at a height of 50 km above the Earth s surface The minimum diameter of a telescope objective on board the satellite which can resolve objects separated by 2mm using a light of wavelength 600 nm is col A 18 3 m B 9 15 m C 18 3 cm D 9 15 cm

If there had been one eye of the man then 1 Image of the object would have been inverted 2 Visible region would have decreased 3 Image would have not been seen three dimensional 4 b and c both

1 w 8 2 8 00 When white light passes through the achromatic combination of prisms then what is observed Only deviation 2 Only dispersion 4 None of the above 3 Deviation and dispersion of ongle of minimum deviation of a prism in air and when dipped in water will be 3 u 3 2 ar

28 In a standard YDSE set up performed with light of wavelength 600 nm one of the slits is covered with a transparent sheet of thickness 12 0 m and refractive index 1 5 If the fringe width is 0 5 mm then the shift in the fringe pattern due to introduction of the sheet is 1 1 mm 3 4 mm 2 3 mm 4 5 mm

09 A beam of light consisting of two wavelengths 800 nm and 600 nm The beam is used to obtain interference fringes in Young s double slit experiment screen kept at a distance 1 4 m away from slits The slits are separated by a distance of 0 28 mm The least distance from central maximum where bright fringes of two wavelengths coincide is O A 3rd bright of 800 nm will coincide with 4th bright of 600 nm O B 4th bright of 800 nm will coincide with 3rd bright of 600 nm C 3rd bright of 800 nm will coincide with 2nd bright of 600 nm O D 2nd bright of 800 nm will coincide with 3rd bright of 600 nm

In case of diffraction pattern of a single slit under polychromatic illumination first minima of wavelength A is found to coincide with the second maxima o wavelength X2 then 3 1 22 2 5 A A 2 5 A 5 A

139 The refracting angle of a prism is A and refractive index of the material of the prism is cot A 2 The angle of minimum deviation is 2015 b 90 A d 180 3A a 180 2A c 180 2A 140 Two identical thin plano convex glass lenses

In a lake a fish is rising vertically to surface of water uniformly at a rate of 3 m s observes a bird diving vertically towards water at a rate of 9 m s The actual velocity of the dive of the bird p 4 3 06ms 1 O 3 6 ms 1 4 5 ms 1 10 ms 1

An interference is observed due to two coherent sources A B separated by a distance 42 along the y axis where is the wavelength of the source A detector D is moved on the positive x axis The number of points on the x axis excluding the points x 0 x at which maximum will be observed is A B D 4 infinite 37 277

An object is kept at infinite distance produces a bright and sharp image on the screen kept at a distance x in front of concave mirror then x is equal to A Radius of curvature B Twice of the focal length C Focal length of the mirror

9 Polarizer and analyzer are set with their polarizing directions parallel so that the intensity of transmitted light is maximum Through what angle should either be turned so that the intensity is reduced to 80 of the maximum intensity 1 Point 30 Degree 26 5 Degree 26 6 Degree 90 Degree

pov It is cut into two symmetrical halves by a plane containing the principal axis and then two pieces are joined as shown in fig The power of the combination will be P A B A B 1 Zerc

13 The condition for minima in Fraunhoffer diffraction for single slit is a sin 8 m A Why m cannot be zero 1 Point For m 0 minima will be formed at the centre of the screen For m 0 diffraction pattern will not be observed at all and screen will be totally bright For m 0 condition for central maxima will be satisfied For m 0 diffraction pattern will not be observed at all and screen will be totally

5 Calculate the minimum thickness of glass plate which appear dark in reflected light for which angle of refraction 60 degree u 1 5 and 5890 AO 1 Point 3 92 10 7m 3 29 10 7m 3 0 10 7m 4 0 10 7m

A beam of light is passed through a polariser and an analyser The latter is then set for maximum inten sity of transmission To reduce the intensity to 1 fraction one tries four ways of turning the analyser A and polariser P 1 A 20 P 40 2 A 75 P 15 4 A 0 P 60 3 A 60 P 0 Here and stand for clockwise and anti clockwise turning Which one will work

A Young s double slit experiment is performed using monochromatic light of wavelength X The intensity of light at a point on the screen where the path difference is is K units The intensity of light at a point where the path difference is is given by where n is an integer The value nk 12 of n is

In Young s double slit experiment on the screen the 5th bright band due to one light of wavelength coincides with 6th bright band due to anothe light of wavelength A Then will be D d are same monochromatic monochromatic 1 1 B 5 6 C 6 5 D 4 5 A

Two beams A and B of plane polarized light with mutually perpendicular planes of polarization are seen through a polaroid From the position when the beam A has maximum intensity and beam B has zero intensity a rotation of polaroid through 30 makes the two beams appear equally bright If the initial intensities of the two beams are I and I respectively then I I equals a 1 3 c 3 2 b 3 d 1

126 A proton accelerated through a potential dif ference of 100V has de Broglie wavelength 20 The de Broglie wavelength of an a par ticle accelerated through 800V is 20 A 2 C 20 4 20 B 2 D 20 8

The waves of 600 m wave length are incident normally on a slit of 1 2mm width The value of diffraction angle corresponding to the first minima will be in radian 1 7 2 3 3 2 56 4

If a thin mica sheet of thickness t and refrective index 5 3 is placed in the path of one of the interfering bean as shown in fig Then the displacement of the fringe system is Question Type Single Correct Type 1 2 3 Dt 3d 2Dt 3d Dt 4d Dt 2d 2D

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 RPMT 1996 MP PET 2000 RPET 2001 MP PMT 2001 b 3 1 d 1 1 a 4 1 c 2 1

In Young s double slit experiment the distance between slits and the screen is 1 0 m and monochromatic light of 600 nm is being used A person standing near the slits is looking at the fringe pattern When the separation between the slits is varied the interference pattern disappears for a particular distance de between the slits If the angular resolution of 1 the eye is the value of d is close to 60 a Imm h 3mm c 2mm d 4mm

A 2m string has tension 1N is fixed at both end and its is vibrating is its third harmonic with antin amplitude 3cm and frequency 100Hz then 32 Possible stationary wave equation for the vibration of the string will be assume origin at left of the string and x is measured in meters towards right and t is measured in seconds B 0 03m sin 3 A y 0 06m cos x sin 100nt 2 C y 0 06m sin 3 4 x cos 200nt D 0 03m cos 3 2 x sin 200rt 3 4 x sin 200nt

What is maximum number of possible interference maximas for YDSE in which slit separation is twice the wavelength of monochromatic light

005 m a real image is formed 0 20 m from the lens vision is 0 24 m ufication is produced by the lens when used as a magnifier The least distance Ans 7 2 x 102 m respectively The objective forms a real image at a distance of 20 x 10 2 m Calculate the 35 In a compound microscope the objective and eye piece have focal lengths of 5 x 10 3 m and magnifying power if the eye is held close to the eye piece and views a virtual image at a distance of 24 x 10 m its least distance of distinct vision Also find the distance between the object and the objective JAns 507 5 13 x 10 m 36 The f

16 Two wave are represented by equation 9 a sin oot 9 a cos cot the first wave 1 leads the second by t 2 lags the second by 3 leads the second by 4 lags the second by RIN 2 EIN 2 to y a u yu y to y k

Transverse waves can propagate 1 only in solids 2 both in solids and gases 3 neither in solids nor in gases 4 only in gases Light

53 When an unpolarized light of intensity I is incident on polarizing sheet the intensity of the light which does r d baget transmitted is a 10 b 22 10 c Io d zero

18 If Io is the intensity of the principal maximum in the single slit diffraction pattern then what will be its intensity when the slit width is doubled a 410 b 210 c Io 2 d Io

3 Focal length of magnifiying lens is 5 cm What will be the maximum magnification possible 1 4 3 6 2 5 4 7

A Young s double slit experiment uses a monochromati source The shape of the interference fringes formed on screen is a circle c parabola b hyperbola d straight line

The time taken by a photoelectron to come out after the photon strikes is approximately a 104s c 10 16 g b d 10 10 s 10 1e

Q7 25 Feb 2021 Shift Imathange mathonga mathongo mathongo Two coherent light sources having intensity in the ratio 2x produce an interference pattern The ratio will be mal 2 2x 1 2 1 zongo max Imax Imin mathongo mathongo mathango 2 2x 1 3 2 2x ngo 2x 1 2z 4 ngomathongemathonga mathongs mathongo mathongo mathongo mathongo mathongo mathongo mathongo mathongo mathongo mathongo

Wave Optics Questions with Answer Keys malt Ampu regthe An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging from the analyzer is measured as 100 onge Lumens Now if the analyzer is rotated around the horizontal axis direction of ongo JEE Main 2021 2019 Chapter wise MathonGo

Figure shows two coherent sources of waves vibrating of phase and separated by a distance of 8 cm P is the nearest point to the axis where constructive interference occurs in a plane and 24 cm from the line joining the sources If S P is 26 cm then the wavelength of the waves in cm is A 4 B 8 C 10 D 16 8 cm S S24 24 cm 14 ca

In the Young s double slit experiment the distance between the slits varies in time ashongomothongs d t do ao sinot where do w and ao are mathongo matho constants The difference between the largest fringe width and the smallest fringe width obtained over time is given as mathongo mothongo 2 3 2AD do d a ongo 2ADao d a3 matonge mathongo AD ao mathongo mathongo mathong mathongo mathongo mathongs mothongo mathongo mothong mathongo mathongo mathongamathong