Wave Optics Questions and Answers

3 central fringe does not exist The maxium number of possible interference maxima for slit separation equal to twice the wavelength in Young double slit experiment is RPMT 2008 1 infinite 3 three 2 five 4 zero hinh omit radiations of RPMT 2005

1 Increase 2 Decrease 3 Remain constant 4 None of these A plane wavefront 6x10 7m falls on a slit 0 4 mm wide A convex lens of focal length 0 8m placed behind the focusses the light on a screen What is the linear diameter of second maximum 1 6mm 2 12mm 3 3mm 4 9mm

Usually light of red colour is used to see the diffraction pattern by single slit If green light issued in place of red li then diffraction pattern 1 will become more bright 3 will expand 2 will become contract 4 will not be seen

In a single slit diffraction the distance between plane of slit and screen is 1 m The size of the slit is 0 7 mm and second maximum is formed at the distance of 2 mm from the centre of the screen then find out the wavelength of light 1 5600 2 2800 3 3000A 4 6000 ce pattern disappears when one of the slits is closed YDSE AIIMS 2018 AIIMS 2018

What will be the angle of diffracting for the first minimum due to Fraunhoffer diffraction with sources of light of wave length 550 nm and slit of width 0 55 mm 2 0 01 rad 1 0 001 rad 3 1 rad 4 0 1 rad Angular width B of central maximum of a diffraction pattern on a single slit does not depend upon

In Fresnel s biprism coherent sources are obtained by 1 Division of wavefront 2 Division of amplitude 3 Division of wavelength 4 None of the above In a Fresnel biprism experiment the two positions of lens give separation between

4 diffraction pattern disappears Two coherent sources S and S having same phase emit light of wavelength The separation between S and S is 2 The light of collected on a screen placed at a distance D A from slit S as shown in figure Find the minimum RPMT 2014 distance so that the intensity at P is equal to intensity at O FI S 2 S

7 1 2 2 0 6 3 2 4 4 1 5 In the Young s experiment using light of 5893 A 62 fringes are observed in the field of view how many frin will be formed in the field of view for wavelength of 5461 A 1 62 2 66 3 67 4 68 unl width are observed when ligh

In the propagation of electromagnetic waves the angle between the direction of propagation and plane of polarisatio is 1 0 2 45 3 90 4 180

Figure represents a glass plate placed vertically on a horizontal table with a beam of unpolarised light falling on its surface at the polarising angle of 57 with the normal The electric vector in the reflected light on screen S will vibrate with respect to the plane of incidence in a 1 Vertical plane 2 Horizontal plane 3 Plane making an angle of 45 with the vertical 4 Plane making an angle of 57 with the horizontal Y6 Y S

A monochromatic plane wave of speed c and wavelength A is diffracted at a small aperture The diagram illustrates successive wavefronts After what time will some portion of the wavefront XY reach P X A 3 2c P

At the first minimum adjacent to the central maximum of a single slit diffraction pattern the phase difference between NEET 2015 the Huygen s wavelet from the edge of the slit and the wavelet from the midpoint of the slit is 2 8 radian 1 radian TC 3 4 radian 4 2 radian

When light of wavelength 540 nm passes through a single slit of unknown width the diffraction pattern displays a second maximum where the first minimum of light of an unknown wavelength had been observed to fall What is the unknown wavelength 540nm Unknown

0 In Young s experiment light wavelength 4000 A is used and fringes are formed at 2 metre distance and has a fringe width of 0 6 mm If whole of the experiment is performed in a liquid of refractive index 1 5 then width of fringe will be 1 0 2 mm The slits in a Young s doubla 2 0 3 mm 3 0 4 mm 4 1 2 mm

c remain same d cor In a 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 JEE Main 2017 a 15 6 mm c 7 8 mm b 1 56 mm d 9 75 mm irst performed in air anc

Choose the correct options Marks 0 5 With the help of which of the following equations is the interplanar distance calculated from a known wavelength of the source and measured angle OPTIONS Bragg equation Poisson equaton Coolidge equation

Two polaroids P P2 are arranged in a line such that their pass axis are at angle of 53 with each other If unpolarised light of intensity lo is incident on polaroid P then intensity of light passing from polaroid P2 will be 91 25 810 625 31 10 910

A light beam is viewed through a rotating analyser One sees a maximum and a minimum of intensity but not complete darkness Incoming light beam should be Unpolarised light beam Completely plane polarised light beam Partially polarised light beam

At a particular point in the medium the resultant displacement produced by a number of waves is the vector sum of the displacements produced by each of the waves Above statement is in accordance with the Law of conservation of energy Principle of superposition Concept of secondary wavelets

Which of the following statement is correct Shape of wave front for light diverging from a point source is spherical Shape of wave front for light emerging out of a convex lens when a point source is placed at its focus is plane The portion of the wave front of light from a distant star intercepted by the earth is hyperbolic Both 1 and 2

In Young s double slit experiment using monochromatic light of wavelength the intensity of light at a point on the screen where path difference is A is y units Intensity of light at a point on screen where path difference is 2 will be O y 2 unit 2 y 3 unit 3 y 2 unit Zero unit

Which of the following statement is correct Most interference and diffraction effects exist for longitudinal as well as transverse waves Polarisation phenomenon are special to transverse waves only Refraction define the limits of ray optics

Which of the following statement is correct about wave front Wave front may be defined as a surface of constant phase It is the locus of points which oscillates in same phase The speed with which the wave front moves outwards from the source is called the speed of the wave O All of the above

Unpolarised light is incident on a plane transparent medium If the reflected and refracted rays are perpendicular to each other then what should be the value of angle of incidence for this to happen of medium 7 5 37 45 54 4 30

Consider the following two statements Statement A A polaroid consists of long chain molecules aligned in a particular direction which is known as pass axis of the polaroid Statement B When unpolarised light falls on polaroid then electric field vectors associated with the propagating light along the pass axis gets absorbed Which of the following option is true Statement A is correct while statement B is incorrect

How many slits per centimetre does a grating have if the third order occurs at a 15 0 angle for 620 nm light A B C D 1580 cm approx 1130 cm approx 1390 cm approx 1240 cm approx O A O O B C

A galaxy is moving with speed v away from us so that the light at 682 nm is observed at 682 4 nm Value of v is nearly equal to 486 km s 523 km s O 176 km s min sec 224 km la

A monochromatic light of wavelength 5600 A is incident normally on a single slit and the diffraction pattern is observed on a screen If the distance between the central bright band and the third dark band is 2 4 cm and slit separation is 0 16 mm find the screen distance from the slit

b The impure sugar weighing 20 gm is dissolved in 150 cc of water It gives an optical rotation of 10 when Polarimeter tube of length 20 cm is used If specific rotation of sugar is 66 dm gm ce determine percentage impurity of sugar

Which of the following statement is incorrect CA Diffraction of sound waves is readily observed than light optical waves OB In Fraunhoffer s class of diffraction source and screen are kept at a large infinite distance from obstacle OC In Fresnel s class of diffraction source and screen are kept at a large infinite distance from obstacle OD Diffraction is exhibited by transverse as well as longitudinal waves

Interference in the thin film will not be observed when 1 Film is illuminated by point source 2 Film s thickness is much greater than coherence length OA Both 1 and 2 are correct OB 1 is incorrect 2 is correct OC 1 is correct and 2 is incorrect OD Both 1 and 2 are incorrect

A Newton s ring arrangement is used with a source emmiting two wavelengths A and A and it is found that nth dark ring of A is coincinding with n 1 dark ring of A Which of the following condition would be correct A OA A B OA A

A glass microscope lens Refractive index g 1 5 is coated with magnesium fluoride film refractive index 1 38 to increase the transmission of normally incident yellow light X 5800 The minimum thickness of the film to be depositted on the lens is A 01050 m B 00 105 m C 010 5 m D 01 05 m

Calculate the angles at which the first dark band will be formed in the fraunhofer diffraction pattern of a slit of width 0 2mm Given 5890 OA 0 1687 degree OB 0 2581 degree Oc 0 1785 degree OD 0 2487 degree

In the YDSE conducted with white light 4000 A 7000 A consider two points P and P2 on the screen at y 0 2 mm and Y2 1 6 mm respectively Determine the wavelengths which form maxima at these points d 1cm S 4m Y2 1 6mm P y 0 2mm

Q 18 In YDSE distance between the slits plane and screen is 1 m and distance between two slits is 5 mm If slabs of thickness 2 mm and 1 5 mm having refractive index 1 5 and 1 4 are placed in front of two slits find the shift in metre of central maxima Rate this questic

How many principal maxima orders will be visible in diffraction pattern if the wavelength of incident light is 5000A and the number of lines on the grating are 3000 lines per cm CA 06 CB 07 Oc 08 OD 09

5 Points Which of the following is readily a good source to form an interference pattern in Young s double slit experiment Select one O Sun light O Florescent light O Lightbulb light O Laser light

Two coherent narrow slits emitting light of wavelength A in the same phase are placed parallel to each other at a small separation of 2A The light is collected on a screen S whic is placed at a distance D A from the slit S as shown in figure Find the finite distance x such that the intensity at P is equal to intensity O S 22 X

Two parallel narrow horizontal slits in an opaque vertical screen are separated center to center by d 5 mm These are directly illuminated by yellow plane waves from a filtered discharge lamp Horizontal fringes are formed on a vertical viewing screen 13 m from the aperture plane The center of the fifth bright band is y 3 mm above the center of the zeroth central bright band a 10 points Determine the wavelength Ao of the light in air Xo b 10 points If the entire space is filled with a special type of oil having a index of refraction n special 1 356 where would the fifth fringe now appear find y y

Part C Coherent light with a wavelength of 700 nm passes through a single slit with a width of 0 15 mm Calculate the angular width of the central diffraction maximum as well as for the second diffraction maximum Hint the width of the central maximum in diffraction formula is inversely proportional to the slit width

Q 11 In Young s double slit experiment two wavelengths of light are used simultaneously where 2 In the fringe pattern observed on the screen then 5th order minima of will coincide with nth order maxima of Then find the value of n Your Answer Rate this quest

Q 17 In YDSE experiment if the screen is shifted by a distance of 0 5 m away from the sl 3rd maxima is shifted by 3 x 10 m If the slit width is 2 10 m if the wavelength used in experiment is 100 n mm then find the value of n X Your Answer Unattempted Rate this que

Q 5 In a usual Young s double slit experiment with 5000 d 2 m m and D 1 m t number of maxima obtained on the screen if it is large enough to receive any number of fringes Answer A 8001 B 6001 C 4001 Rate this que

When light of wavelength 600 nm is used in Young s double slit experiment 8 fringes are observed on the screen If wavelength of light is changed to 400nm how many fringes will be observed on the screen Options 1 2 12 14

An equiconvex lens is placed on another equiconvex lens The radii of curvatures of the two surfaces of the upper lens are 50 cm and those of the lower lens are 100 cm The waves reflected from the upper and lower surface of the air film formed between the two lenses interfere to produce Newton s rings Calculate the radii of the dark rings Assume X 6000 A Ans 0 0447 m cm

Two slits in a Young s double slit experiment produce on a screen Their initial phases are identical A maxima is formed at the central point on the AD screen What will be the intensity of light at a distance from the central maxima Here 3d is the wavelength of light used d is the slit separation and D is the distance of the screen from the shift

29 The velocity of electromagnetic radiation in a medium of permittivity and permeability o is given by b Mo Eo a Eo Mo 1 Mo Eo d Ho VE

ZERO MARKS in all other cases In Young s double slit experiment the distance between slits is 2 x 104 m The adjacent maxima of interference pattern subtend an angle of 10 8 minutes at the midpoint between slits The value of of light used in the experiment is nearly 6 280x10 k m Find k Answer Keypad

Find the sILILL An object placed in front of a convex mirror produces an image half the size of the object On shifting the object through 20 cm magnification is reduced to 1 4 Calculate the focal length of 10 cm the mirror