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

A pond appears to be 2 . 7 m deep. If the refractive index of water is 4 3 , find the actual depth of the pond.

The refractive index of the material is a unitless quantity on which the speed of light a medium depends. It is the ratio of real depth to apparent depth. Given, the apparent depth d A = 2 . 7 m , refractive index of water μ = 4 3 , let the real depth be d R μ = d R d A 4 3 = d R 2 . 7 m d R = 4 3 × 2 . 7 m = 3 . 6 m Hence, the real depth is 3 . 6 m .

The refractive indices of water and diamond are 4 3 and 2 . 42 respectively. Find the speed of light in water and diamond. c = 3 × 10 8 m s - 1

Given: Refractive index of water, μ w = 4 3 . Refractive index of diamond, μ d = 2 . 42 . We know that the refractive index of water is μ w = V a V w = 4 3 V w = V a μ w = 3 × 10 8 4 3 = 2 . 25 × 10 8 m s - 1 . Similarly, the refractive index of diamond is μ d = V a V d = 2 . 42 V d = V a μ d = 3 × 10 8 2 . 42 = 1 . 23 × 10 8 m s - 1 . Speed of light in water is 2 . 25 × 10 8 m s - 1 . Speed of light in diamond is 1 . 23 × 10 8 m s - 1 .

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According to diagram, fish see two image of observer first through refraction only and other due to refraction and then reflection. Distance of the images from fish are $S_{1}$ and $S_{2}$ respectively observer can also see the two images of fish, first due to refraction only and other due to reflection and then refraction. Distance of them image from observer are $S_{3}$ and $S_{4}$ respectively :-

COLUMN-I COLUMN-II

(A) $S_{1}$ (P) $H [1 + \frac{1}{2 μ}]$

(B) $S_{2}$ (Q) $H [μ + \frac{1}{2}]$

(C) $S_{3}$ (R) $H [1 + \frac{3}{2} μ]$

(D) $S_{4}$ (S) $H [μ + \frac{3}{2}]$

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Important Questions on Ray Optics

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

A monochromatic beam of light passing through water (refractive index

= 4 / 3

) has wavelength

5400 Å .

When it is refracted in glass (refractive index

= 3 / 2

) its wavelength will be

MEDIUM

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

A ray of light wavelength

λ_{0}

and frequency v₀ enters a glass slab of refractive index

μ

from air. Then,

MEDIUM

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

Light of wavelength

5000 \overset{o}{A}

in air has wavelength in glass

(μ = 1.5)

equal to:

MEDIUM

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

Blue light travelling in a vacuum has a wavelength of

450 nm .

It enters a medium whose refractive index is

1.5 .

What is its frequency in the medium?
(Speed of light in vacuum

= 3 \times 10^{8} m s^{- 1}

)

MEDIUM

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

A vessel of depth

2 h

is half filled with a liquid of refractive index

2 \sqrt{2}

and the upper half with another liquid of refractive index

\sqrt{2}

. The liquids are immiscible. The apparent depth of the inner surface of the bottom of the vessel will be

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

Light of wavelength

300 nm

in medium

A

enters into medium

B

through a plane surface. If the frequency of light is

5 \times 10^{14} Hz

and the ratio of speed in medium

A

to that is medium

B

\frac{4}{5}

, the absolute refractive index of medium

B

is,

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

Which one of the following physical quantities does not have unit?

MEDIUM

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

A pond appears to be

2.7 m

deep. If the refractive index of water is

\frac{4}{3}

, find the actual depth of the pond.

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

Choose the wrong statement.

MEDIUM

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

Frosted glass is widely used for translucent windows. The region, where a transparent adhesive tape is stuck over the frosted glass becomes transparent. The most reasonable explanation for this is

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

Which of the following graphs shows appropriate variation of refractive index

μ

with wavelength

λ

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical 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

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

A converging lens forms a real image

I

on its optic axis. A rectangular glass slab of refractive index

μ

and thickness

t

is introduced between the lens and the image

I

. The image

I

will move

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

The wavelength of a light coming from a sodium source is

645 nm

. What will be its wavelength in water, if the refractive index of water is

1.33 ?

MEDIUM

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

If the difference in the velocities of light in glass and water is

0.25 \times 10^{8} m / s

, calculate the velocity of light in air. Given that refractive index of glass and water with respect to air are

1.5

and

\frac{4}{3}

respectively.

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

If the refractive indices of water and glass are

\frac{4}{3}

and

\frac{3}{2}

respectively. The refractive index of glass with respect to water is

MEDIUM

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

The refractive indices of water and diamond are $\frac{4}{3}$ and $2.42$ respectively. Find the speed of light in water and diamond. $(c = 3 \times 10^{8} m s^{- 1})$

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

When a plane electromagnetic wave enters a glass slab, then which of the following will not change?

EASY

Physics>Optics>Ray Optics>Refraction at Plane and Spherical Surfaces

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

MEDIUM

Physics>Optics>Ray Optics>Refraction at Plane and Spherical 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:

	COLUMN-I		COLUMN-II
(A)	$S_{1}$	(P)	$H [1 + \frac{1}{2 μ}]$
(B)	$S_{2}$	(Q)	$H [μ + \frac{1}{2}]$
(C)	$S_{3}$	(R)	$H [1 + \frac{3}{2} μ]$
(D)	$S_{4}$	(S)	$H [μ + \frac{3}{2}]$

Important Questions on Ray Optics

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