1.

What are the laws of reflection ?

a)

angle of incidence = angle of reflection

b)

incident ray , reflected ray and the normal at the point of incidence all are in the same plane

c)

incident ray , refracted ray and the normal at the point of incidence all are in the same plane

d)

$\frac{Sin\ i}{Sin\ r\ }=\frac{^n2}{\ ^n1}$

2.

What are the laws of refraction ?

a)

angle of incidence = angle of reflection

b)

incident ray , refracted ray and the normal at the point of incidence all are in the same plane

c)

incident ray , reflected ray and the normal at the point of incidence all are in the same plane

d)

$\frac{Sin\ i}{Sin\ r\ }=\frac{^n2}{\ ^n1}$

3.

Radius of curvature of a plane mirror

a)

zero

b)

infinity

c)

can be zero or infinity

d)

25 cm

4.

Angle between the incident and reflected ray falling on a plane mirror is 60⁰ . Find the angle of incidence ( i )and reflection (r)

a)

i = r = 60

b)

i = r = 30

c)

i = r = 45

d)

i = 30 , r = 60

5.

Image formed by a plane mirror is

a)

real inverted and magnified

b)

virtual erect and enlarged

c)

virtual erect and same size

d)

virtual erect and diminished

6.

Image formed by a plane mirror is

a)

real inverted and magnified

b)

virtual erect and enlarged

c)

virtual erect and same size

d)

virtual erect and diminished

7.

Focal length of a convex mirror of radius of curvature (R) 20 cm is

a)

f = -20 cm

b)

f =-10 cm

c)

f = +10 cm

d)

f = +20 cm

e)

f = +40 cm

8.

Focal length of a concave mirror of radius of curvature (R) 20 cm is

a)

f = -20 cm

b)

f =-10 cm

c)

f = +10 cm

d)

f = +20 cm

e)

f = +40 cm

9.

A concave mirror forms complete image of a small candle placed in front of it on a screen. If the lower half of the mirror is cut and removed (or painted black) .

a)

complete image will be formed

b)

Half of the image will be formed

c)

intensity (brightness) of the image decreases

d)

Intensity (brightness) of the image remains the same

10.

A convex lens forms complete image of a small candle placed in front of it on a screen. If lower half of the lens is painted black.

a)

complete image will be formed

b)

Half of the image will be formed

c)

intensity (brightness) of the image decreases

d)

Intensity (brightness) of the image remains the same

11.

A concave mirror of focal length 10 cm forms complete image of a small candle placed in front of it on a screen. If the mirror is cut in to two identical halves new focal length is

a)

f = -10 cm

b)

f = -20 cm

c)

if = - 5 cm

d)

f = + 10 cm

12.

A convex lens of focal length 10 cm forms complete image of a small candle placed in front of it on a screen. If the lens is cut in to two identical halves along the principal axis,new focal length is

a)

f = -10 cm

b)

f = -20 cm

c)

if = - 5 cm

d)

f = + 10 cm

13.

An equi - convex lens of focal length 10 cm forms complete image of a small candle placed in front of it on a screen. If the lens is cut in to two identical halves normal to the principal axis,new focal length is

a)

f = -10 cm

b)

f = -20 cm

c)

if = +20 cm

d)

f = + 10 cm

14.

If the colour of the incident light is changed from violet to red, focal length of a mirror

a)

increases

b)

decreases

c)

remains the same

d)

may increase or decrease

15.

If the colour of the incident light is changed from violet to red, focal length of a convex lens

a)

increases

b)

decreases

c)

remains the same

d)

may increase or decrease

16.

ASSERTION (A) If a convex lens is cut in to two identical halves, focal length becomes double.

REASON (R) For a lens focal length f = R/2 , where R = radius of curvature

a)

A & R are true and R is the correct explanation for A

b)

A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

Both A & R are false

17.

ASSERTION (A) Critical angle of glass is less than critical angle of water .

REASON (R) Refractive index of water is less than that of glass

a)

A & R are true and R is the correct explanation for A

b)

A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

Both A & R are false

18.

ASSERTION (A) Critical angle of glass slab placed air is less than critical angle of glass slab placed in water .

REASON (R) Refractive index of glass with respect to water is less than critical angle of glass with respect to air

a)

A & R are true and R is the correct explanation for A

b)

A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

Both A & R are false

19.

ASSERTION (A) When a glass(n =3/2) prism is placed in water(n = 4/3), the angle of minimum deviation decreases and critical angle of the prism increases .

REASON (R) Refractive index of glass with respect to water is < Refractive index of glass with respect to air

a)

A & R are true and R is the correct explanation for A

b)

A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

Both A & R are false

20.

ASSERTION (A): If a convex lens ( n =1.5) is is immersed in water(n= 4/3). focal length of the lens increases

REASON (R): Refractive index of lens with respect to water is less than the refractive index of lens with respect to air

a)

A & R are true and R is the correct explanation for A

b)

A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

Both A & R are false

21.

ASSERTION (A): If a concave mirror made of glass ( n =1.5) is is immersed in water(n= 4/3). focal length of the mirror increases

REASON (R): Refractive index of glass with respect to water is less than the refractive index of glass with respect to air

a)

A & R are true and R is the correct explanation for A

b)

A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

Both A & R are false

22.

ASSERTION (A): If a concave mirror made of glass ( n =1.5) is is immersed in water(n= 4/3). focal length of the mirror increases

REASON (R): Refractive index of glass with respect to water is less than the refractive index of glass with respect to air

a)

A & R are true and R is the correct explanation for A

b)

A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

Both A & R are false

23.

Focal length of a mirror depends on

a)

refractive index of the glass used

b)

the radius of curvature

c)

object distance and image distance

d)

colour of the incident light

e)

refractive index of the medium in which it is placed

24.

focal length of a lens depends on

a)

refractive index of the glass used

b)

the radius of curvature

c)

object distance and image distance

d)

refractive index of the medium in which lens is placed

e)

colour of incident light

25.

A convex lens

a)

is always converging

b)

is always diverging

c)

can be converging or diverging according to the refractive index of the medium in which it s placed

d)

act as converging lens for | u | > f and diverging for | u | < f

26.

A concave lens

a)

is always converging

b)

is always diverging

c)

can be converging or diverging according to the refractive index of the medium in which it s placed

d)

act as converging lens for | u | > f and diverging for | u | < f

27.

An air bubble under water act as a

a)

converging lens

b)

diverging lens

c)

neither converging nor diverging

d)

can be converging or diverging according to the radius of curvature

28.

A water drop in air act as a

a)

converging lens

b)

diverging lens

c)

neither converging nor diverging

d)

can be converging or diverging according to the radius of curvature

29.

Correct expression for focal length of lens is

a)

$\frac{1}{f}=\frac{1}{v\ }-\frac{1}{u}$

b)

$\frac{1}{f}=\ \frac{1}{v\ }+\frac{1}{u\ }$

c)

f = R/2

d)

$\frac{1}{f}=\left(\frac{n_2}{n_1}-1\right)\left(\ \frac{1}{R_1}-\frac{1}{R_2\ }\right)$

e)

$f\ =\frac{1}{P\ }$

30.

Correct expression(s|) for focal length of mirror is

a)

$\frac{1}{f}=\frac{1}{v\ }-\frac{1}{u}$

b)

$\frac{1}{f}=\ \frac{1}{v\ }+\frac{1}{u\ }$

c)

f = R/2

d)

$\frac{1}{f}=\left(\frac{n_2}{n_1}-1\right)\left(\ \frac{1}{R_1}-\frac{1}{R_2\ }\right)$

e)

$f\ =\frac{1}{P\ }$

31.

As the object approach the pole of a concave mirror, from infinity,

a)

size of the image decreases as long as | u | > | f |

b)

size of the image increases when | u | < | f |

c)

image distance increases from zero to infinity for | u | > | f |

d)

image distance increases from f to infinity for | u | > | f |

32.

Single concave lens

a)

always form virtual image

b)

always form real image

c)

can form real as well as virtual images

d)

forms a point size image at f for object at infinity

e)

| v | < | f |

33.

Single convex mirror

a)

always form virtual image

b)

always form real image

c)

can form real as well as virtual images

d)

forms a point size image at f for object at infinity

e)

| v | < | f |

34.

Single concave mirror

a)

always form virtual image

b)

always form real image

c)

can form real as well as virtual images

d)

forms a point size image at f for object at infinity

35.

Single convex lens

a)

always form virtual image

b)

always form real image

c)

can form real as well as virtual images

d)

forms a point size image at f for object at infinity

36.

For real image formation, the least distance between the object and image of a convex lens of focal length 10 cm is

a)

10 cm

b)

20 cm

c)

40 cm

d)

infinity

e)

zero

37.

For real image formation, the least distance between the object and image of a concave mirror of focal length 10 cm is

a)

10 cm

b)

20 cm

c)

40 cm

d)

infinity

e)

zero

38.

A convex lens forms an image of on electric bulb (fixed on a wall) on the opposite wall. If the distance between the walls is 4 m, what is the maximum focal length of the lens used for the purpose?

a)

$\frac{4}{3\ }m$

b)

$\frac{5}{3}m$

c)

4 m

d)

1 m

39.

A convex lens is placed on the top of a plane mirror. If the image coincides with the object at a distance of 40 cm from the combination focal length of the lens is

a)

40 cm

b)

20 cm

c)

10 cm

d)

80 cm

40.

A screen is placed at 100 cm from the object and a lens forms an image with magnification , m = -1 on the screen. Find the focal length of the lens

a)

f = - 25 cm

b)

f = + 25 cm

c)

f =+50 cm

d)

f = -50 cm

41.

Correct expression for magnification of lens is

a)

$m\ =\frac{v}{u}$

b)

$m=-\frac{v}{u}$

c)

$m\ =\ \frac{f}{f\ -u}$

d)

$m\ =\ \frac{f-v}{f}$

e)

$m\ =\ \frac{f}{f+u}$

42.

Correct expression for magnification of a mirror is

a)

$m\ =\frac{v}{u}$

b)

$m=-\frac{v}{u}$

c)

$m\ =\ \frac{f}{u\ -f}$

d)

$m\ =\ \frac{v-f}{f}$

e)

$m\ =\ \frac{f}{f+u}$

43.

An object is placed at distance equal to the focal length of convex mirror. If the focal length of the mirror is 20 cm, then

a)

image is formed at infinity

b)

image is formed 10 cm on the other side of the object

c)

image is formed 10 cm on the same side of the object

d)

magnification of the image is m = +1/2

e)

magnification of the image is m =-1/2

44.

An object is placed at distance equal to the focal length of concave lens. If the focal length of the lens is 20 cm, then

a)

image is formed at infinity

b)

image is formed 10 cm on the other side of the object

c)

image is formed 10 cm on the same side of the object

d)

magnification of the image is m = +1/2

e)

magnification of the image is m =-1/2

45.

During refraction through glass slab placed in air, for oblique incidence

a)

angle of incidence = angle of emergence

b)

refracted ray is parallel to the incident ray extended

c)

angle of emergence > angle of incidence

d)

refracted ray bends away or towards the incident ray according to angle of incidence

46.

During refraction through glass slab placed in air, lateral displacement

a)

increases with angle of incidence

b)

increases with thickness of glass slab

c)

increases with refractive index of the glass slab

d)

increases with decrease in wavelength of light incident

e)

decreases if air replaced by water

47.

A point object placed in denser medium of thickness t refractive index b , when observed from a rarer medium of refractive index a

a)

$\frac{actual\ depth}{apparet\ depth}=\frac{b}{a}$

b)

$shift\ =\ t\ \left(\ 1\ -\frac{a}{b}\right)\$

c)

$\frac{actual\ depth}{apparent\ depth}=\frac{a}{b}$

d)

$shift\ =\ t\left(\ 1-\ \frac{b}{a}\right)\$

48.

Conditions for total internal reflection are

a)

angle of incidence > critical angle of the medium

b)

angle of incidence < critical angle of the medium

c)

light must be moving from rarer to denser medium

d)

light must be moving from denser to rarer medium

49.

Refractive index of a medium is $\sqrt[]{2}$ . Total internal reflection will take place if

a)

light moves from air to the medium with i > 45

b)

light moves from air to the medium with i < 45

c)

light moves from the medium to air with i > 45

d)

light moves from the medium to air with i < 45

50.

Select correct options related to total internal reflection, when light moves from a denser to a rarer medium

a)

$SinC=\frac{n_r}{n_d}$

b)

i = c, r = 90, refracted ray move parallel to the surface of separation

c)

i < C , light undergo refraction and bend away from the normal

d)

i > C , light undergo TIR with angle reflection = angle of incidence

e)

i = 0, r = 0, light move along the line of incidence without any deviation

51.

A point source of light is placed at the bottom of denser medium of depth H and refractive index n. what is the minimum radius of an opaque disc to be placed on the top of the medium so that no light emerges out of the medium to air

a)

R =H tan C,

if C = critical angle

b)

$R\ =\frac{H}{\sqrt[]{n^2-1}}$

c)

$R\ =\frac{H}{\sqrt[]{n^2+1}}$

d)

$R\ =\ \frac{H}{n^2-1}$

52.

Critical angle of a medium

a)

$C\ =Sin^{-1}\left(\ \frac{n_r}{n_d}\right)$

b)

increases with decrease in wavelength of light used

c)

decreases with decrease in wavelength of light used

d)

decreases with increase in refractive index of the denser medium

e)

increases when the refractive index of the rarer medium increases

53.

Which is true?

a)

nb > nc > na

b)

nc > nb > na

c)

na > nc > nb

d)

nb > na > nc

e)

none of the above

54.

If the critical angle is between water and air is 48.6 degrees, what will the fish see at 60 degrees?

a)

The object in the air

b)

The object on the surface of the water

c)

The object on the sea floor

d)

nothing

55.

Light is travelling from air to water. Which path will the light most likely follow?

a)

A

b)

B

c)

C

d)

D

e)

E

56.

Critical angle of water air interface is approximately 48⁰. When light travel from air to water for which angle of incidence total internal reflection will take place?

a)

50⁰

b)

46⁰

c)

45⁰

d)

42⁰

e)

Total internal reflection will not take place.

57.

An equiconvex lens of focal length 15 cm is cut into two halves as shown in figure. Find the focal length of each part?

a)

-30cm

b)

30cm

c)

20cm

d)

7.5 cm

58.

A glass lens is immersed in water. What will be the effect on the power of lens?

a)

increase

b)

decrease

c)

constant

d)

not depends

59.

The optical density of turpentine is higher than that of water while its mass density is lower

shows a layer of turpentine floating over water in a container. For which one of the four

rays incident on turpentine in the path shown is correct?

a)

1

b)

2

c)

3

d)

4

60.

A short pulse of white light incident from air to glass slab at normal incidence. After travelling through the slab the first colour to emerge is

a)

violet

b)

blue

c)

green

d)

red

61.

Two lenses of focal lengths 20 cm and - 40cm are held in contact. If an object lies at infinity, image formed by the lens combination will be at

a)

infinity

b)

40cm

c)

20cm

d)

60cm

62.

The characteristic feature of light which remains unaffected on refraction is

a)

speed

b)

wavelength

c)

frequency

d)

velocity of light

63.

When a convex lens placed inside a transparent medium of refracting index greater than

that of its own material, it behave as

a)

diverging lens

b)

converging lens

c)

Plane glass

d)

can act as a diverging or converging lens according to the thickness of the lens

64.

The deviation $\delta$ of a ray on passing through a prism of small angle A is

a)

$\delta\ =\left(\mu-1\right)A$

b)

$\delta\ =\left(\mu+1\right)\ A$

c)

$\delta=\left(\ A-1\right)\mu$

d)

$\delta=\left(A+1\right)\mu$

65.

The radius of curvature of the curved surface of a plano-convex lens is 20 cm. If the refractive index of the material of the lens be 1.5, it wil

a)

act as a convex lens only for the objects that lie on its curved

side.

b)

act as a concave lens for the objects that lie on its curved side.

c)

act as a convex lens irrespective of the side on which the object

lies.

d)

act as a concave lens irrespective of side on which the object lies

66.

The refractive indices of four materials A, B, C and D are 1.33, 1.43, 1.71 and 1.52 respectively. When the light rays pass from air into these materials, the speed of light is minimum in

a)

material A

b)

material B

c)

material C

d)

material D

67.

A student obtained a sharp image of the grill of a window on a screen, using a convex lens. For getting better results, the teacher suggested focussing of a distant tree instead of the grill. In which direction should the lens be moved for this purpose?

a)

towards the screen

b)

away from the screen

c)

to behind the screen

d)

very far away from the screen

68.

A teacher sets up a stand carrying a convex lens of focal length 15cm at 42.7cm mark on the optical bench. He asks four students A, B, C and D to suggest the position of the screen on the optical bench so that a distinct image of a distinct tree is obtained almost immediately on it. The positions suggested by the students are 12.7cm, 29.7cm, 57.7cm and 72.7. The correct position of the screen is?

a)

57.7 cm

b)

12.7 cm

c)

72.7 cm

d)

29.7 cm

69.

A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed.

a)

60 cm behind the lens, size of the image = +1.25 cm

b)

60 cm in front of the lens, size of the image = +1.25 cm

c)

8.5 cm behind the lens, size of the image = +1.76 cm

d)

8.5 cm in front of the lens, size of the image = +1.76 cm

70.

ASSERTION(A): dentist use concave lens for observations inside mouth.

REASON(R) When object is placed between the pole and focus of a concavelens enlarged virtual image is formed

a)

Both A & R are true and R is the correct explanation for A

b)

Both A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

both A & R are false

71.

ASSERTION(A): convex mirrors are used as rear view mirrors

REASON(R) irrespective of the position of the object a convex mirror forms virtual erect diminished image within the focus hence provides a large field of view

a)

Both A & R are true and R is the correct explanation for A

b)

Both A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

both A & R are false

72.

ASSERTION (A) : Concave mirrors can be used as shaving mirrors to see a larger image of the face .

REASON(R) : For an object placed between the focus and the pole of a concave mirror forms virtual erect and enlarged image behind the mirror.

a)

A & R are true and R is the correct explanation for A

b)

A & R are true but R is not the correct explanation for A

c)

A is true but R is false

d)

A is false but R is true

e)

Both A & R are false

73.

When light passes through a triangular prism, at minimum deviation

a)

$r_1=r_2=\frac{A}{2}$

b)

$i\ =e\ =\frac{A+D}{2}$

c)

refracted ray passes through the prism parallel to the base of the prism

d)

$i\ =\ e\ =\frac{A-D}{2}$

74.

For light ray undergoing refraction through a prism

a)

d = i + e - A

b)

A = r₁ + r₂

c)

d - A = i + e

d)

A = r₁- r₂

75.

A convex lens and concave lens of equal focal length 10 cm each are placed in contact in air. The resultant focal length and power are .............cm.& .............D respectively

a)

20 , 0.05

b)

10 , 0.1

c)

-20 , -0.05

d)

0 , infinity

e)

infinity , zero

76.

Name the component of visible light which has highest angle of minimum deviation through a glass prism

a)

violet

b)

red

c)

green

d)

blue

e)

yellow

77.

A hollow prism is placed in water, the light ray coming out of the prism deviate,.......

a)

towards the base of the prism

b)

Away from the base of the prism at both the surfaces

c)

will go straight without refraction

d)

towards base on refraction at first surface and away from base on refraction at second surface.

e)

away from base on refraction at first surface and towards base on refraction at second surface.

78.

Identify the correct variation of angle of emergence with increase in angle of incidence

a)

angle of emergence decreases

b)

angle of emergence increases

c)

angle of emergence first decreases then increases

d)

angle of emergence first increases then decreases

79.

Identify the correct variation of angle of deviation with increase in angle of incidence

a)

angle of deviation decreases

b)

angle of deviation increases

c)

angle of deviation first decreases then increases

d)

angle of deviation first increases then decreases

80.

A ray of light is incident on one of the faces of a glass prism(A = 60⁰ ) with angle of incidence same as the angle of the prism. Refracted ray inside the prism strikes the opposite face which is silvered and the reflected ray from it retraces its path. What is the refractive index of the material of the prism.

a)

2

b)

1.5

c)

1.414

d)

1.732

81.

For a glass prism (refractive index, μ =√3 ) the angle of minimum deviation is equal to the angle of the prism. Calculate the angle of the prism in degrees

a)

30

b)

60

c)

45

d)

90

82.

A light ray undergo moves from a rarer medium ( n = a) to convex spherical denser medium ( n = b) of radius of curvature R, then

a)

$\frac{b}{v}-\frac{a}{u\ }=\frac{b-a}{R}$

b)

$\frac{a}{v}-\frac{b}{u}=\frac{b-a}{R}$

c)

$\frac{b}{v\ }-\frac{a}{u}=\frac{a-b}{R}$

d)

$\frac{a}{v}-\frac{b}{u}=\frac{a-b}{R}$

83.

For two thin lenses placed in contact,

a)

P = P₁ + P₂

b)

f = f₁ + f₂

c)

$\frac{1}{P}=\frac{1}{P_1}+\frac{1}{P_2}$

d)

$\frac{1}{f}=\frac{1}{f_1}+\frac{1}{f_2}$

e)

m = m₁ x m₂

84.

For a convex lens made of glass (n =1.5)placed in air

a)

R₁ is positive and R₂ is negative

b)

R₁ is negative and R₂ is positive

c)

f and P are positive

d)

f and P are negative

e)

f & P can be +ve or -ve

85.

For a concave lens made of glass (n =1.5)placed in air

a)

R₁ is positive and R₂ is negative

b)

R₁ is negative and R₂ is positive

c)

f and P are positive

d)

f and P are negative

e)

f & P can be +ve or -ve

86.

A convex lens forms a sharp image on a screen when a parallel beam of light is incident along the principal axis. If thick glass slab is placed between the lens and the screen, for getting a clear image

a)

screen has to be moved closer to the lens

b)

screen has to be moved farther from the lens

c)

no change is needed in the set up

d)

distance between screen and lens may be increased or decreased according to position of the glass slab

87.

Two convex lenses ( f₁ = 12cm and f₂ = 20 cm)are placed in air co-axially with a distance D between them so that a parallel beam of light incident parallel to the principal axis on the first lens leaves the second lens parallel to the principal axis, then D =

a)

32 cm

b)

8 cm

c)

64 cm

d)

16 cm

88.

A convex lenses ( f₁ = 25 cm) and a concave lens ( f₂ = 20 cm)are placed in air co-axially with a distance D between them so that a parallel beam of light incident parallel to the principal axis on the first lens leaves the second lens parallel to the principal axis, then D =

a)

10 cm

b)

45 cm

c)

90 cm

d)

5 cm

89.

A real image, p times the size of the object is formed by a concave mirror of focal length f. What is the object distance?

a)

$\frac{\left(p+1\right)f}{p}$

b)

$\frac{\left(p-1\right)f}{p}$

c)

$\frac{pf}{\left(p+1\right)}$

d)

$\frac{pf}{p-1}$

90.

A ray of monochromatic light passes through an equilateral glass prism in such a way that the angle of incidence is equal to the angle of emergence and each of these angles is 3/4 times the angle of the prism. Determine the angle of (a) deviation and the (b) refractive index of the prism

a)

(a) d = 30

(b) n = $\sqrt[]{2}$

b)

(a) d = 60

(b) n = $\sqrt[]{2}$

c)

(a) d = 30

(b) n = $\sqrt[]{3}$

d)

(a) d = 60

(b) n = $\sqrt[]{3}$

91.

A symmetric biconvex lens of radius of curvature R and made of glass of refractive index 1.5, is placed on a layer of liquid placed on top of a plane mirror as shown in the figure. An optical needle with its tip on the principal axis of the lens is moved along the axis until its real, inverted image coincides with the needle itself. The distance of the needle from the lens is measured to be x. On removing the liquid layer and repeating the experiment, the distance is found to be y. Obtain the expression for the refractive index of the liquid in terms of x and y

a)

$\mu=\frac{\left(2x-y\right)}{x}$

b)

$\mu=\frac{\left(2x-y\right)}{y}$

c)

$\mu=\frac{\left(2y\ -x\right)}{x}$

d)

$\mu=\frac{\left(2y-x\right)}{y}$

92.

An object is placed at a distance of 15 cm from a convex lens of focal length 10 cm. On the other side of the lens, a convex mirror is placed at its focus such that the image formed by the combination coincides with the object itself. Find the focal length of the convex mirror

a)

15 cm

b)

20 cm

c)

30 cm

d)

25 cm

e)

10 cm

93.

The distance between an object and screen is fixed as D. A convex forms images on the screen for two positions of the lens separated by a distance d, focal length of the convex lens is

a)

$f=\frac{\left(D^2-d^2\right)}{4D}$

b)

$f\ =\frac{\left(d^2-D^2\right)}{4D}$

c)

$f=\frac{\left(D^2-d^2\right)}{4d}$

d)

$f=\frac{\left(d^2-D^2\right)}{4D}$

94.

Three light rays R , G and B are incident on a right angled prism 'abc' at face 'ab'. The refractive indices of the material of the prism for R , G and B are 1.39 , 1.414 and 1.47 respectively. Select the correct option

a)

All the three colours undergo total internal reflection at ac and comes out through bc along the normal

b)

Only light ray R comes out through ac and bend away from the normal while B & G come out through bc after total internal reflection from ac

c)

Only light ray B come out through bc, light ray G move along the surface ac and light ray R comes out through ac

d)

All the three come out through ac after refraction through the prism

95.

Three light rays R , G and B are incident on a right angled prism 'abc' at face 'ab'. The refractive indices of the material of the prism for R , G and B are 1.39 , 1.44 and 1.47 respectively. Select the correct option

a)

All the three colours undergo total internal reflection at ac and comes out through bc along the normal

b)

Only light ray R comes out through ac and bend away from the normal while B & G come out through bc after total internal reflection from ac

c)

Only light ray B come out through bc, light ray G move along the surface ac and light ray R comes out through ac

d)

All the three come out through ac after refraction through the prism

96.

Light rays are incident on a glass slab from air with angle of incidence greater than the critical angle of glass with respect to air, then

a)

Light rays undergo total internal reflection and reflect back with angle of incidence = angle of reflection

b)

Light rays move along the surface of separation of glass slab and air

c)

light rays undergo refraction and bend towards the normal

d)

light rays undergo refraction and bend away from the normal

97.

An equi convex lens ( n = 1.5) is placed on the top of a plane mirror with a liquid between the lens and the mirror. A needle is moved along the principal axis so that the inverted image of the needle coincides with the object needle at 40 cm from the mirror. If the experiment is repeated by removing the liquid, the new distance where the object coincides with the image is measured to be 30 cm, then

a)

focal length of convex lens is = 40 cm

b)

focal length of convex lens is = 30 cm

c)

focal length of the liquid lens is = 40 cm

d)

focal length of the liquid lens is = -90 cm

98.

An equi convex lens ( n = 1.5) is placed on the top of a plane mirror with a liquid between the lens and the mirror. A needle is moved along the principal axis so that the inverted image of the needle coincides with the object needle at 40 cm from the mirror. If the experiment is repeated by removing the liquid, the new distance where the object coincides with the image is measured to be 30 cm, then

a)

focal length of convex lens is = 40 cm

b)

focal length of the liquid lens is = -120 cm

c)

focal length of the liquid lens is = 40 cm

d)

focal length of the liquid lens is = -90 cm

99.

An equi convex lens ( n = 1.5) is placed on the top of a plane mirror with a liquid between the lens and the mirror. A needle is moved along the principal axis so that the inverted image of the needle coincides with the object needle at 40 cm from the mirror. If the experiment is repeated by removing the liquid, the new distance where the object coincides with the image is measured to be 30 cm, then

a)

focal length of convex lens is = 40 cm

b)

refractive index of the liquid is 1.25

c)

focal length of the liquid lens is = 30 cm

d)

refractive index of the liquid is 1.33

100.

An object is placed at a distance of 15 cm from a convex lens of focal length 10 cm. A concave mirror is placed after the convex lens at a suitable distance d = 50 cm from the lens so that final image formed by the system coincides with the actual object. Find the focal length of the concave mirror

a)

f = -10 cm

b)

f = -20 cm

c)

f = + 10 cm

d)

f = +20 cm

RAY OPTICS BASICS

Total questions: 100

Worksheet time: 2hrs 52mins

Three light rays R , G and B are incident on a right angled prism 'abc' at face 'ab'. The refractive indices of the material of the prism for R , G and B are 1.39 , 1.414 and 1.47 respectively. Select the correct option

Three light rays R , G and B are incident on a right angled prism 'abc' at face 'ab'. The refractive indices of the material of the prism for R , G and B are 1.39 , 1.44 and 1.47 respectively. Select the correct option

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