Wave Optics Questions and Answers

The 2 A tank is filled with water to a height of 12 4 cm appar ent depth of needle lying at the bottom of the tank is mea sured by a microscope to be 9 3 cm What is the refractive index of water If water is replaced by a liquid of refractive index 1 6 up to the same height by what distance would the microscope have to be moved to focus on the needle CBSE 09 1 33 7 47 cm again

4 The height of a vessel is 15 cm Liquid is poured into the vessel such that the surface of the liquid remains 5 cm below the vessel s top On seeing from above the depth of the liquid appears to be half Calculate the refractive index of the liquid Kerala CET Engg 03 2

3 A rectangular block of thickness 10 cm and refractive index 1 5 is placed on a small coin A beaker is placed on the block and water of height 10 cm is poured in the beaker What will be the apparent position of the coin 3 when viewed normally from above 2 14 17 cm below the surface of water

An object is placed at a distance of 21 cm from a concave mirror of radius of curvature 10 cm Now a glass slab of thickness 3 cm and refractive index 1 5 is placed between the object and the mirror Determine the position of the final image The distance of the nearer face of the slab from the mirror is 1 cm 7 67 cm

A convex lens of focal length 40 cm is placed in system of coordinate axis such that its optical centre is at origin and principal axis coinciding with x axis The coordinates of a point object in front of the lens is 50 cm 5 cm The coordinates of image formed by lens is 50 cm 5 cm Object 0 0

7 Refractive index of a glass prism ABC 1 5 It is immersed in water is w 3 as shown in the Fig 2 90 Show that a ray incident normally on the face AB will undergo total internal reflection at AC if sin B C 0 Fia 2 5

The graph drawn between velocity and frequency of EM wave in vacuum will be hr min Straight line parallel to frequency axis Straight line parallel to velocity axis Straight line passing through origin and making an angle of 45 with frequency axis Hyperbola

35 Two identical glass u 3 2 equiconvex lenses of focal length f are kept in contact The space between the two lenses is filled with water u 4 3 The focal length of the combination is b f 2 a f 4 f 3 f f

A source S is kept directly behind the slit S in a double slit apparatus What will be the phase difference at P if a liquid of refraction index u is filled wavelength of light in air is due to the source assume T d D d 1 Between the screen and the slits II Between the slits the source S In this case find the minimum distance between the points on the screen where the intensity is half the maximum intensity on the screen S S21 D P O Screen

8 Interference fringes are observed on a screen by illuminating two thin slits 1 mm apart with a light source 632 8 nm The distance between the screen and the slits is 100 cm If a bright fringe is observed on a screen at distance of 1 27 mm from the central bright fringe then the path difference between the waves which are reaching this point from the slits is close to 1 2 87nm 2 2 nm

4 The three regions shown in Fig 1 are all lossless and nonmagnetic Determine the standing wave ratio for E in the left region when d equals a 0 b 5 cm c 8 cm ER1 1 Incident wave 500 MHz ER2 9 d ER3 4 5

Consider a YDSE arrangement shown in the figure two transparent glass plates each of thickness t and refractive index 1 2 1 4 are placed in front of slits S and S2 respectively Then a liquid of refractive index 1 6 is filled between slits S S and screen as shown If S S d and Ao is the wavelength of light in air then A e D fauz Afg af d u sta 1 2 1 4 3 5 5421 B C XoD 1 6d 1 ad guadai 1 6 2m 97 ea tef GJMZ HA my heartf A point O is Pag 04 318 1 216 1 1 1 4 t D Xo D D O The distance of central maxima from tD 8d tD 8d Correct Answer Your Answer The central maxima will occur at O 3 YDSE Fringe width in above YDSE will be Xo D 1 6d stoft Correct Answer Your Answer The fringe width in above YDSE will be

25 Two coherent sources of light are placed at points 5a 2 0 and 5a 2 0 Wavelength of the light is 4a 3 How many maximas will be obtained on a CD planar circle of large radius with centre at origin A 12 B 15 C 16 D 14

3 10 cm divergent cm convergent 4 The wavelength of light used in two young s double slit experiments are 400 nm and 500 nm If the fringe width are equal when the screen are placed at 1 2 m and 1 6 m respectively The ratio of the distance between the slits is 1 415 110 2 4 334 n W AG 3

A diverging lens of focal length 20 cm having refractive index 1 5 is immersed in a liquid of refractive index 3 The focal length and nature of the lens in liquid is 1 20 cm divergent 3 10 cm divergent 2 20 cm convergent 4 10 cm convergent

A student and his lab partner create a single slit by carefully aligning two razor blades to a separation of 0 460 mm When a helium neon laser at 594 nm illuminates the slit a diffraction pattern is observed a screen 1 35 m beyond the slit Calculate the angle dark to the first minimum in the diffraction pattern and the width of the central maximum HINT a the angle 8 dark to the first minimum in the diffraction pattern in degrees 0 001297 x b the width of the central maximum in m 3 48 x m

A ray of light is successively deflected from two plane mirrors inclined to each other at a certain angle If the total deviation in the path of the rays reflected from the two mirrors be 300 then what is the number of images can be formed of an object placed between them otions 30

In Young s double slit experiment 500nm d 1mm D 1m Minimum distance from the central maximum for which intensity is half of the maximum intensity is a 2 5 10 4 m c 0 625 10 4 m b 1 25 x 10 4 m d 0 3125 x 10 4m

Two coherent point sources S and S emit light of wavelength A The separation between the sources is 3 Consider a line passing through S and perpendicular to the line S S The smallest distance from S where a minima of intensity will occur is where kis J a far UN ZAGA GR 21 g a feq g y mam tu a Paris y i am AA8 S 3 11X k 11X k

5 A galaxy moving with speed 150 km s shows blue shift At what wavelength sodium line of 580 0 nm will be observed 1 580 29 nm 3 581 nm 2 579 71 nm 4 575 2 nm

A screen is placed above a plane mirror with its surface parallel to mirror If a point source is placed just above the plane mirror then fringe pattern obtained on screen Options 1 Circular 2 Elliptical 3 Strips 4 No fringe pattern v le obtained

Monochromatic light is incident on a plane interface AB between two media of refractive indices and H2 2 at an angle as shown in figure The angle is infinitesimally greater than the critical angle two media so that total internal reflection takes place Now if a transparent slab DEFG of uniform thickness a having refractive index 3 is introduced on the interface as shown in the figure Which of the following statements are correct D G Medium I Medium III 3 E F B Medium II If 3 total internal reflection will take place at face GF If 3 1 light will refract into the slab

In a Young s double slit experiment light consisting of two wavelengths 500 nm and 22 700 nm is incident normally on the slits Find the distance from the central maxima where the maximas due to two wavelengths coincide for the first time after central maxima 1000 where D is the distance between the slits and the screen and d is the separation between the slits Given 2004 D d

Figure shows a Young s double slit experiment set up The source S of wavelength 4000 A oscillates along y axis according to the equation y sin t IS IS where y is in millimeters and t is in seconds The 0 0 0 5mm F distance between two slits S and S is 0 5 mm y S2 1m A The position of the central maxima as a function of time is 4 sinnt B The position of the central maxima as a function of time is 4 sinnt C The instant at which maximum intensity occurs at P for first time is 1 sin T 4m 59 80 D The instant at which minimum intensity occurs at P for this first time is sin 27 80 P

A ray of light is incident at the origin at an angle 60 with Y axis as shown in figure The 2 refractive index is a function of y according to the relation shown in figure Y b H 3 3 The path of the light followed after successive refraction is as shown X 1 y c 3 1 What is the value of H d None

5 In YDSE the two slits are separated by 0 1 mm and they are at 0 5 m distance from the screen The wavelength of light used is 5000 A The distance between 7th maxima and 11th minima the screen 1 8 75 mm 2 4 mm 3 6 32 mm 4 5 8 mm

A parallel monochromatic light 600nm falls normally on a circular aperture of diameter 0 12cm and is viewed from the opposite side along a line through the center of the hole and normal to its plane Calculate the three larger distance from the hole at which the intensity is zero

3 40 When a red light of wavelength 6500 A is incident on a slit in a single slit diffraction experiment and first minima for red light is at 30 then the slit width is 1 5 2 x 10 m 3 1 3 x 10 m 2 2 6 x 10 m 4 1 x 10 m

In Young s double slit experiment if the intensity at the centre of screen is lo then intensity at a distance from the central maxima is here 4 B fringe width 1 lo 2 4 ON gle lo

View in English d In Young s double slit experiment 10 4 d distance between slits D distance of screen from the slits at a point P on the screen the resulting intensity is equal to the intensity due to individual slit lo Then the distance of point P from the central maximum is A 6000 A D 1 2 3 4 orrect Answer 1 atus unattempted 2 mm Imm 0 5 mm 4 mm

A glass slab of thickness 5 cm contains the same number of waves as 6 cm of water when both are traversed by the same monochromatic light If the refractive index of water is 4 3 then that of glass is A 5 3 B 5 4 C 8 5 D 3 2

Online Mock Test Series for NEET 2020 40 The first diffraction minimum due to a single slit diffraction is at 0 30 for a light of wavelength 5000 A The width of the slit is 2 1 0 x 10 cm 4 1 25 x 10 5 cm 1 5 x 10 5 cm 3 2 5 x 10 5 cm

0 In YDSE let be the fringe width and be the intensity at distance from central maxima What will be the intensity of central maxima 1 21 2 41 3 31 4 410 3

Example In a Newton s ring experiment the diameters of nth and n 5 th dark rings are 0 114 cm and 0 142 cm respectively Find the diameters of i n 5 th ii n 10 th dark rings

A telescope can just resolve Rayleigh Criterion two objects which are 2000 km away from it If the separation between objects is 10 m and the wavelength of light used is 500 nm then the minimum diameter of the objective of the telescope is O 12 2 cm O 24 4 cm O 30 0 cm O 48 8 cm

Online Mock Test Series for NEET 2020 1 A ray of light falls from air on a prism of refractive index 2 at an angle with the normal What should be the maximum value of i for which the total internal reflection will take place at side AC 1 30 3 60 B 75 2 2 45 4 90 C

please explain which of the following method is correct a nd why In a Fraunhofer diffraction experiment at a single slit using a light of wavelength 400nm the first minimum is formed at an angle of 30 The direction of the first secondary maximum is given by bein Dani 9 30 Mal N 1 b sim 3go x ng b 200hm b sind n o bsing x or foox sind 4 00 Sin 8 0 sin 14 Direction of the first secondary maximum in the Fraunhofer diffraction pattern at a single slit is given by a is the width of the slit a asin 0 c a sin 0 b a cose d asin0 32 2 32 2 asing asino 2n 1 3x Asked by 3319883 aesl id Standard XII Stream NEET Aug 2 2021 at 11 56 PM Add your responses Type Text Type your answer here OR you can upload an attachment from the option below

Unpolarised light is incident from the air on a plane surface of a material of refractive index p At a particular angle of incidence it is four reflected and refracted rays are perpendicular to each other Which of the following options is correct for this situation 1 The reflected light is polarised with its electric vector parallel to the plane of incidence 2 The reflected light is polarised with its electric vector perpendicular to the plane of incidence 3 i sin 4 1 tan

M In a Young s double slit experiment slits are separated by a distance d and screen is at distance D D d from slit plane If light source of wavelength d is used The minimum distance from central point on the screen where intensity is one fourth of the maximum is Find the value of n DN nd

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 is a unchanged c doubled b halved d four times

5 In Young s double slit experiment the y co ordinates of central maxima and 10th maxima are 2 cm and 5 cm respectively When the YDSE apparatus is immersed in a liquid of refractive index 1 5 the corresponding y co ordinates will be

1 Fresnel s biprism having an angle of 1 and the index of refraction 1 5 form interference fringes on a screen placed 80 cm from the biprism If the distance between slit and the biprism is 30 cm find the fringe separation B when the wavelength of light used is 5000 A

3 Interference fringes are produced by monochromatic light falling normally on a wedge shaped film of cellophane whose refractive index is 1 4 The angle of wedge is 20 seconds of arc and the distance between successive fringes is 0 25 cm Calculate the wavelength of light used

36 In the Young s double slit experiment the intensity of light at a point on the screen where the path difference is 2 is K being the wave length of light used The intensity at a point where the path difference is 4 will be 1 K A 2 K 4 3 K 2 4 zero 7 fre KDORANDUGEOWIN D WA MO

A source S and a detector D are placed at a distance d apart A big cardboard is placed at a distance 2d from the source and the detector as shown in figure 16 E2 The source emits a wave of wavelength d 2 which is received by the detector after reflection from the cardboard It is found to be in phase with the direct wave received from the source By what minimum distance should the cardboard be shifted away so that the reflected wave becomes out of phase with the direct wave S 201

Solution with explanation What is the angle of incidence for an equilateral prism of refractive index 3 so that ray is parallel to the base inside the prism 1 30 3 60 2 45 4 Any angle of minimum deviation and refractive index of its material is

In Nehru Planetarium an astronomical telescope which has an objective lens of diameter 10 m To 7000 A What will anything through this telescope planetarium team glow a light of wavelength the resolving power of this telescope A 54 6 106 B C 23 7 10 11 7 105

Corridor figure shows an overhead view of a corridor with a plane mirror M mounted at one end A burglar B sneaks along the corridor directly toward the center of the mirror If d 6m how far in m from the mirror will she be when the security guard S can first see her in the mirror M to B S P

Refractive index of diamond with respect to the glass is 1 6 and absolute refractive index of the glass is 1 5 Find the speed of the light in the diamond 1 25 x 108 ms 1 2 5 x 108 ms 1 2 4 x 108 ms 1 2 108 ms 1

2 14 The central fringe of the interference pattern produced by light of wavelength 6000 is found to shift to the position of fourth bright fringe after a glass plate of refractive index 1 5 is introduced in path of one of beams The thickness of the glass plate would be 1 4 8 mm 2 8 23 mm 3 14 98 mm 4 3 78 mm