A ray of light wavelength λ 0 and frequency v 0 enters a glass slab of refractive index μ from air. Then,

Δ λ = λ 0 1 μ - 1 and Δ v ⁡ = 0

Its wavelength increases, frequency decreases

Its wavelength increases, frequency remains same

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A parallel beam of light of width $t$ is incident at an angle $45^{0}$ on air-water boundary. The refractive index of water is $μ$ . The width of beam in water is

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Important Questions on Ray Optics and Optical Instruments

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

When the same monochromatic ray of light travels through glass slab and through water, the number of waves in glass slab of thickness

6 cm

is same as in water column of height

7 cm

. If refractive index of glass is

1.5

then refractive index of water is

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

A transparent slab of thickness

d

has a refractive index

n (z)

that increases with

z

. Here

z

is the vertical distance inside the slab, measured from the top. The slab is placed between two media with uniform refractive indices

n_{1} and n_{2} (> n_{1}),

as shown in the figure. A ray of light is incident with angle

θ_{i}

from medium 1 and emerges in medium 2 with refraction angle

θ_{f}

with a lateral displacement

l

. Which of the following statement(s) is (are) true?
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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

A horizontal parallel beam of light passes through a vertical convex lens of focal length,

20 cm

and is then reflected by a tilted plane mirror so that it converges to a point

I

. The distance

P I

10 cm

M

is a point at which the axis of the lens intersects the mirror. The distance

P M

10 cm

. The angle which the mirror makes with the horizontal is,

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

A cubical vessel has opaque walls. An observer (dark circle in the figure below) is located, such that she can see only the wall, $C D$ , but not the bottom. Nearly to what height should water be poured, so that she can see an object placed at the bottom at a distance of, $10 cm$ , from the corner, $C$ ? Refractive index of water is, $1.33$ .

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

Consider a plane parallel beam of light incident on a plano-cylindrical lens as shown below. Which of the following will you observe on a screen placed at the focal plane of the lens?

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

Let the refractive index of a denser medium with respect to rarer medium be

n_{12}

and its critical angle be

θ_{C}

. At an angle of incidence

A

when light is travelling from denser medium to rarer medium, a part of the light is reflected and the rest is refracted and the angle between reflected and refracted rays is

90^{o}

. Angle

A

is given by

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

A light wave is incident normally on a glass slab of refractive index

1.5 .

4 %

of light gets reflected and the amplitude of the electric field of the incident light is

30 \frac{V}{m},

then the amplitude of the electric field for the wave propagating in the glass medium will be:

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

A ray of light

A O

in vacuum is incident on a glass slab at angle

60 °

and refracted at angle

30 °

along

O B

as shown in the figure. The optical path length of light ray from

A

B

is:

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

When light travels from an optically rarer medium to an optically denser medium, the velocity of light decreases because of change in

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

From a prism of refracting angle $60^{o}$ , the angle of minimum deviation is $30^{o}$ . Calculate:

$(ii)$ the angle of refraction

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

Electromagnetic waves emanating from a point $A$ (in air) are incident on a rectangular block of material $M$ and emerge from the other side as shown below. The angles $i$ and $r$ are angles of incidence and refraction when the wave travels from air to the medium. Such paths for the rays are possible,

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

Select the correct statement about rainbow.

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

The angles of incidence and refraction of a monochromatic ray of light of wavelength

λ

at an air-glass interface are

i

and

r,

respectively. A parallel beam of light with a small spread

δ λ

in wavelength about a mean wavelength

λ

is refracted at the same air-glass interface. The refractive index

μ

of glass depends on the wavelength

λ a s μ (λ) = a + \frac{b}{λ^{2}}

where a and b are constants. Then the angular speed in the angle of refraction of the beam is

HARD

Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

A girls sees through a circular glass slab (refractive index

1.5

) of thickness

20 mm

and diameter

60 cm

to the bottom of a swimming pool. The refractive index of water is

1.33

. The bottom surface of the slab is in contact with the water surface.
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The depth of the swimming pool is

6 m

. The area of the bottom of the swimming pool that can be seen through the slab is approximate-

MEDIUM

Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

The angle of a prism is ‘

A

’. One of its refracting surfaces is silvered. Light rays falling at an angle of incidence

2 A

on the first surface returns back through the same path after suffering reflection at the silvered surface. The refractive index

μ,

of the prism is:

MEDIUM

Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

The reflected ray is completely polarized for certain angle of incidence in a transparent medium. If the angle of refraction is

30 °,

then the refractive index of the medium is

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

When light enters glass from vacuum, then the wavelength of light

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Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

A ray of light wavelength

λ_{0}

and frequency v₀ enters a glass slab of refractive index

μ

from air. Then,

EASY

Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

In refraction, light waves are bent on passing from one medium to second medium because, in the second medium.

MEDIUM

Physics>Optics>Ray Optics and Optical Instruments>Refraction at Plane Surfaces

A small object is enclosed in a transparent solid sphere of radius

8 cm

. The object is situated at

2 cm

from the centre of the sphere. If its image appears to be at

3.2 cm

from the nearest side then the refractive index of the material of the sphere is

A parallel beam of light of width t is incident at an angle 450 on air-water boundary. The refractive index of water is μ . The width of beam in water is

Important Questions on Ray Optics and Optical Instruments

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A parallel beam of light of width $t$ is incident at an angle $45^{0}$ on air-water boundary. The refractive index of water is $μ$ . The width of beam in water is