Geometrical Optics Questions and Answers

5 in physics complete reflection of a ray of light within a medium such as water or glass from the surrounding surfaces back into the medium The phenomenon occurs if the angle of incidence is greater than a certain limiting angle called adium of refractive inley 165 What is the nature of the lens

16 67 8 sini sinr Refractive index of a glass as light ray passes from air to glass is given by n COGNITIONS experiment i and r were found to be 45 3 and 30 3 then error in n is nearly A 0 28 B 0 20 C 0 15 D 0 143 times and 3 V5 The ratio of earth s surface area as covered by two communication satellite moving 5 1 required with orhital speed of In a certain times that of G MEG A m 2 kg A The y

13 Assertion when the object moves with a velocity 2 metre per second its image in the plane mirror moves with a velocity of 4 metre pers econd Reason The image formed by a plane mirro r is as far behind the mirror as the object is i n front of it

4 Each angle of a prism is 60 and the refractive index of a monochromatic light is 3 This light is incident at correct angle for minimum deviation The deviation of the portion of the light which finally emerges from the prism after having one internal reflection 120 Incorrect You Marked 270 B D 240 180 Correct

If a lens is moved towards the object from a distance of 20 cm to 15 cm the magnification of the image remains the same The focal length of the lens is O 15 5 cm O 16 8 cm O 17 5 cm O 12 6 cm

Two parallel beams of light pass through an isosceles prism of refractive index 1 4 as shown in the figure The angle between the two emergent rays is in degree sin35 0 57 sin 0 798 53 35 35 110 C

2 A black spot on the surface of a glass sphere of 3 refractive index u 2 opposite position It appears to be at a distance of 10 cm from spot Diameter of sphere is 1 5 cm 2 10 cm is viewed from diametrical

An object of size 3 cm is placed 14 cm in front a convex mirror of focal length 21 cm Size of th image when object is moved farther from the mirror 1 Increasing 2 Decreasing 3 Same

A point object O is placed in front of a glass rod having a spherical end of radiu of curvature 30 cm The image would be formed at 1 5 0 Air 15 cm Glass 30 cm 30 cm to the left infinity 1 cm to the right 18 cm to the left

diver looking up through the water sees the outside world contained in a circular horizon The refractive index of water is and the diver s eyes are 15 cm below the surface of water Then the radius of the circle is O 15 x 3 x 5 cm O 15 x 3 7 cm O 15x 7 cm 2 15x3 i cm

point object in air is in front of the curved surface of a plano convex lens The radius of curvature of the curved surface is 30 cm and the refractive index of the naterial is 1 5 then the focal length of the lens in cm is

0 A ball is dropped from a height of 20 m above the surface of water in a lake The refractive index of water is 4 3 A fish inside the lake in the line of fall of the ball is looking at the ball At an instant when the ball is 12 8 m above the water surface the fish sees the speed of ball as Take g 10 m s 1 a 9 m s b 12 m s s 1 d 20 m s c 16 m s 1

6 A convex lens of focal length 20 cm is placed in front of a plane mirror as shown in the figure 20 cm An object O is placed in front of convex lens For what value of x final image will coincides with the object 2 40 cm 4 All of the above 1 20 cm 3 30 cm 37 In the following circuit the output Y for all porsible inputs A and B is expressed by the truth organ pipe is 1 3 m 3 4 m 42 A conductor placed perper AB carrying c A 2 1 B The magn Ho 2 41

For a spherical surface of radius of curvatures R separating two media of refractive index and the two principal focal lengths are f and f respectively Which relation is correct A f f B f f 2 C f f D f f H

25 A light ray is incident on the composite slab as shown in the figure Angle made by the light ray with the normal in medium 3 will be 45 air p 45 2 3 29 A particle in a certain conserva a potential energy given by U 3 26 If the de Broglie wavelength of an electron in the ohr s orbil be A then the minimum radial exerted on it is 102 10x 10

A converging lens f 13 6 cm is held 7 60 cm in front of a newspaper the print size of which has a height of 1 96 a Find the image distance in cm d cm b The height in mm of the magnified print h mm

8 A hemispherical portion of the surface of a solid glass sphere of refractive index 1 5 and of radius r is silvered to make the inner side reflecting An object is placed at the axis of the sphere at a distance 3r from the center of the sphere The light from the object is refracted at the unsilvered part then reflected from the silvered part and again refracted at the unsilvered part Locate the final image formed Solution 1 5 For first refraction at the unsilvered surface we have V So V r r i e rays become parallel to the principal axis Hence the image formed by the curved mirror will lie at the focus of the mirror i e a distance from pole of mirror from pole of the mirror For second refraction at the unsilvered surface we have 1 1 5 1 V 2r r 1 5 V 48 1 1 5 1 V 2R O

A telescope consists of two thin lenses of focal lengths 0 3 m and 3 cm respectively It is focussed on Moon which subtends an angle of 0 5 at the objective Then the angle subtended at the eye by the final image will be Question Type Single Correct Type 1 2 5 0 25 3 0 5

In a double slit experiment the distance between the slits is d The screen is at a distance D from the slits If a bright fringe is formed opposite to a slit on the screen the order of the fringe is 1 3 d 2ND d 2 d 2 D 4 Zero

The rear face of an equiconvex glass lens of focal length 30 cm is silvered so that it behaves like a concave mirror An object is placed at a distance of 7 5 then find 3 Ug 2 the distance of final image from the silvered lens cm in front of this silvered lens If O 10 cm O O 30 cm 40 cm

If there is a very small air bubble inside a glass sphere 1 5 of radius 10 cm at distance 4 cm below its surface then its apparent depth when viewed normally from outside of nearer surface will be approximately O2 cm 2 4 cm 3 1 cm 3 6 cm

mass m is ins electric gure with direction in particle uiter Q 29 A light ray in medium RI C 5 3 enters another medium at an angle 30 The angle in other medium is sin 5 6 The incident angle must be increased such that the ray is completely reflected at minimum degrees is

The power of the lens is 2D What is the focal length and nature of the lens Converging lens of focal length 0 5 m Converging lens of focal length 50 cm Diverging lens of focal length 50 cm Diverging lens of focal length 5 m

A convex lens made of glass with refractive index 2 is placed in a medium of refractive index A parallel beam of light entering the lens Odiverges converges undergoes no refraction O comes out as a parallel beam by itself

5 A compound microscope uses an objective lens of focal length 4cm and eyepiece of focal length 10cm An object is placed 6cm from the objective lens Calculate the maximum magnifying power of the compound microscope Assume normal near point is at 25cm 1 2 3 4 2 7 4 8

2 Rear window of a car has a size of 120 x 45 cm 32 The driver sits at a distance L 2m from the rear window What should be the minimum size of flat mirror hanging at a distance of 0 5 m in front of the driver so that he has best view of road situation behind the car 1 24 cm x 9 cm 2 30 cm x 11 25 cm 3 40 cm x 15 cm 4 20 cm x 7 5 cm fect forget an er 120 x 45 cm L 2m 1 da fecit fag 0 5 a Efen auf 1 24 cm x 9 cm 2 30 cm x 11 25 cm 3 40 cm x 15 cm 4 20 cm x 7 5 cm der

58 Two plane mirrors are inclined at 70 A ray incident on one mirror at angle 0 after reflection falls on second mirror and is reflected from there parallel to first mirror The value of 0 is NEET Kar 2013 a 50 c 30 b 45 d 55

A narrow parallel beam of light falls on a glass sphere of radius R and refractive index at normal incidence The distance of the image from the outer is given by KVPY 2010 R 2 a b 2 1 c R 2 2 1 R 2 2 1 d R 2 2 1

A convex lens of focal length 20 cm and a concave mirror having their principal axes along the same lines are kept 80 cm apart from each other The concave mirror is to the right of the convex lens When an object is kept at a distance of 30 cm to the left of the convex lens its image remains at the same position even if the concave mirror is removed The maximum distance in cm of the object for which this concave mirror by itself would produce a virtual image would be

A lens of focal length f 40 cmis cut along the diameter into two equal halves In this process a layer of thickness t 1 mm is lost The halves are then put together to form a composite lens In between focal plane and the composite lens a narrow slit is placed symmetrically very close to the focal plane such that u f The slit is emitting monochromatic light of wavelength 0 6 m Behind the lens a screen is located at a distance L 0 5 m from it as shown f 40 cm TuleIfl 0 5 m Screen 0 Fringe width is 0 12 mm Fringe width is 0 24 mm

3 A ray of light passes from a denser medium to a rarer medium at an angle of incidence i Th reflected and refracted rays make an angle of 90 with each other The angle of reflectio and refraction are respectively r and r The critical angle is given by 1 sin tanr 2 sin cotr 3 tan sini 4 sin tanr

A plane trapezium is in a plane containing principal axis of a lens It s real image is formed The image is of the shape of a square The side length of square will be A 1 5 cm B 2 cm C 3 cm D 6 cm 3cm A D 2cm B C 1cm

A transparent cylinder of radius R and height H made from a material of refractive index 1 5 is placed on a horizontal tabletop and a point light source is placed at a height h above the centre of top circular face of the cylinder Find unilluminated area on the tabletop outside the cylinder

The refractive index of diamond is 2 4 2 This statement tells that the speed o f light in diamond is 2 42 times less th an the speed of light in air plzz tell am I correct or incorrect answer in yes or no plz

What is the near point of a person whose eyes have an accommodated power of 58 0 D Assume that the distance from the cornea to the retina is 2 0 cm 8 00 cm

A broad beam of light is incident on a reflex surface If entire beam focuses at a single p P then nature of reflecting surface is 1 Parabolic 2 Spherical 3 elliptical 4 hyperbolic

A light ray is coming parallel to principal axi the distance between ray and axis is equal focal length as shown Find the angle c deviation after reflection N 1 60 2 90 3 120 4 180 2tan 0 5 The image produced by a concave mirror is on

A ray of light travelling in the direction i 31 is incident on a plane mirror After reflection it travels along the direction i 3 The angle of incidence is 1 30 2 45 3 60 4 75 An object is approaching a fixed plane mirror with speed 15 ms making an angle of 135 with the normal to the mirror The speed of 6 image w r t mirror is 1 15 ms AS object fixed 2 15 3 15 2 ms 4 30 ms An object is placed at 100 cm from plane 8 mirror It approaches towards mirror with a velocity 8 cm s Calculate magnitude of displacement of image with respect to object in 5 sec 1 60 cm 2 40 cm 3 120 cm 4 80 cm If two mirrors are kept at 60 to each other then the number of images formed by them is 3 5 2 3 4 6 AB is incident wavefront on mirror R and mirror S whereas PQ and P Q is reflected wavefront from mirror R and mirror S respectively Choose the CORRECT statement 1 7 mirar R 31 1 mirror R is concave and mirror S is convex 2 mirror R is plane and mirror S is convex 3 mirror R is plane and mirror S is concave 4 mirror R is convex and mirror S is plane Refer to the figure The number of reflections from mirrors M and M are 1 5 and 5 2 6 and 5 3 10 and 10 4 6 and 6 Plane mirror and an object has speeds of 5 ms and 10 ms respectively If the motion of mirror and object is along the normal of the mirror then the speed of image may be 1 0 ms 3 20ms 2 10 ms 4 Both 1 and 3 A point object O can move along vertical line AB as shown in figure When image of the object is first visible to D then it is released at t 0 from rest The time for which image of object is visible to D is E Vertical plane 5 39 5 10

6 A convex lens of focal length 1 0 m and a concave lens of focal length 0 25 m are 0 75 m apart A parallel beam of light is incident in the convex lens The beam emerging after refraction from both lenses is a parallel to principal axis b convergent c divergent d none of these

4 6 and 6 Plane mirror and an object has speeds of 5 ms and 10 ms respectively If the motion of mirror and object is along the normal of the mirror then the speed of image may be 1 0 ms 2 10 ms 3 20ms 4 Both 1 and 3

Consider the diagram shown here f 40 cm 2 cm s 30 cm y 2 cm x 13 cm X An object O is approaching two halves of a lens placed according to diagram Choose the correct answer 1 At the instant shown x coordinate of images H 120 cm 2 30 cm

A point object O is going towards concave mirror as shown in the figure Choose the correct option representing direction of velocity of the image F is the focus and C is the centre of curvature 1 t F 2

The image produced by a concave mirror is quarter the size of object when the objec 12 5 cm from mirror If the object is mo 5 cm closer to the mirror the image will only half the size of the object The focal lengti mirror is 1 f 5 0 cm 1 f 75 cm 2 f 2 5 cm 4 f 10 cm

59 Consider the ray diagrams for a concave mirror focal length fM and a convex lens focal length fr in air as shown in the figure below if What happens to their focal lengths when they are immersed in a medium of refractive index higher than that of air fM A fM changes and fr stays same B fM stays same and fr changes C both fM and fL changes D both fM and fr stay same

Paraxial ray is that incident ray which is 1 Any ray parallel to principle axis 2 Any ray making small angle with principle axis 3 Ray incident close to pole and making small angle with principle axis 4 Ray incident at pole at any angle

The refractive index of the medium with a certain region x 0 y 0 changes with y A thin light ray travelling in the x direction in medium having refractive index 1 strikes another medium of refractive index u at right angles and moves through the medium along a circular arc of radius R as shown in the figure The material with the greatest known refractive index is diamond but even the refractive index of this material does not reach the value Hmax 2 5 It is this limit that sets the maximum angular size of the are the light ray can cover Angular size of are is the angle subtended by the arc at the centre 3

9 An equilateral glass prisms kept on a table has refractive index of u 2 It is illuminated by a marrow laser bearn having power P and wavelength The path of the laser beam inside the prism is parallel to the base of the prism The change in reading of weight of the prism due to the incident Po X Find x y e is the speed of light Ignore any partial reflection luser beam is le A Weighing machine

If object starts moving with 2 cms perpendicular to principal axis above the principal axis having real image two times magnified then 1 Image moves with velocity 4 cms below the principal axis 2 Image moves with velocity 4 cms above the principal axis 3 Image moves with velocity 8 cms below the principal axis 4 Image moves with velocity 8 cms above the principal axis

As shown in figure ABC is right angled isosceles prism kept in air A ray of light is incident on it normally as shown The refractive index for the material of prism is given by u 1 0 4t here t is in second The angular velocity of the emergent ray at t 1 is 1 1 2 rad s 3 2 rad s B C 2 1 rad s 4 1 5 rad s

3 Four combination of two thin lenses lens and mirror are given in list I The radius of curvature of all curved surfaces is same and the refractive index of all the lenses is 1 5 Focal length of a biconvex lens kept in air with same radius is f Match lens combination in list I with their equivalent focal length in air in list II and select the correct answer using the code given below the lists List I P Q R S 1 II AD A P 3 Q 2 R 4 S 1 C P 4 Q 2 R 3 S 4 1 2 List II 4 3 f 4 2f B P 3 Q 3 R 4 S 1 D P 2 Q 4 R 1 S 3