Ray Optics Refraction(11th And 12th > Physics ) Questions and answers for exam Preparation

11th And 12th > Physics

RAY OPTICS REFRACTION MCQs

Total Questions : 15 | Page 1 of 2 pages

Question 1.

Refractive index for a material for infrared light is

[CPMT 1984]

Equal to that of ultraviolet light
Less than for ultraviolet light
Equal to that for red colour of light
Greater than that for ultraviolet light

Discuss Question

Answer: Option B. -> Less than for ultraviolet light
:
B

$Refractive Index For A Material For Infrared Light Is [CPMT...$

Question 2.

A monochromatic beam of light passes from a denser medium into a rarer medium. As a result [CPMT 1972]

Its velocity increases
Its velocity decreases
Its frequency decreases
Its wavelength decreases

Discuss Question

Answer: Option A. -> Its velocity increases
:
A

Question 3.

The ratio of the refractive index of red light to blue light in air is
[CPMT 1978]

Less than unity
Equal to unity
Greater than unity
Less as well as greater than unity depending upon the experimental arrangement

Discuss Question

Answer: Option A. -> Less than unity
:
A

$The Ratio Of The Refractive Index Of Red Light To Blue Light...$

Question 4.

Monochromatic light is refracted from air into the glass of refractive index $Monochromatic Light Is Refracted From Air Into The Glass Of ...$ The ratio of the wavelength of incident and refracted waves is

[JIPMER 2000; MP PMT 1996, 2003]

Discuss Question

Answer: Option C. ->

:
C

$Monochromatic Light Is Refracted From Air Into The Glass Of ...$

Question 5.

When light is incident on a medium at angle i and refracted into a second medium at an angle r, the graph of sin i vs sinr is as shown in the graph. From this, one can conclude that

$When Light Is Incident On A Medium At Angle I And Refracted ...$

Velocity of light in the second medium is 1.73 times the velocity of light in the I medium
Velocity of light in the I medium is 1.73 times the velocity in the II medium

Discuss Question

Answer: Option B. -> Velocity of light in the I medium is 1.73 times the velocity in the II medium
:
B
$When Light Is Incident On A Medium At Angle I And Refracted ...$

Question 6.

In the adjoining diagram, a wavefront AB, moving in air is incident on a plane glass surface XY. Its position CD after refraction through a glass slab is shown also along with the normals drawn at A and D. The refractive index of glass with respect to air (μ=1 ) will be equal to

$\frac{s i n θ}{s i n θ^{'}}$
$\frac{s i n θ}{s i n ϕ^{'}}$
$\frac{s i n ϕ^{'}}{s i n θ}$
$\frac{A B}{C D}$

Discuss Question

Answer: Option B. ->

\frac{s i n θ}{s i n ϕ^{'}}

:
B

in the case of refraction is CD is the refracted waves front and $V_{1}$ and $V_{2}$ are the speed of light in
the two media, then in the time the wavelets from B reaches C, the wavelets from A will reach D,
such that

$t = \frac{B C}{v_{a}} = \frac{A D}{v_{g}} \Rightarrow \frac{B C}{A D} = \frac{v_{a}}{v_{g}} . . . (i)$
But in $△ A C B, B C = A C s i n θ . . . (i i)$
While in $△ A C D, A D = A C s i n ϕ^{'} . . . (i i i)$
From equations (i), (ii) and (iii) $\frac{v_{a}}{v_{g}} = \frac{s i n θ}{s i n ϕ^{'}}$
Also $μ \propto \frac{1}{v} \Rightarrow \frac{v_{a}}{v_{g}} = \frac{μ_{g}}{μ_{a}} = \frac{s i n θ}{s i n ϕ^{'}} \Rightarrow μ_{g} = \frac{s i n θ}{s i n ϕ^{'}}$

Question 7.

The refractive index of a certain glass is 1.5 for light whose wavelength in vacuum is 6000 . The wavelength of this light when it passes through glass is

[NCERT 1979; CBSE PMT 1993; MP PET 1985, 89]

4000 Å
6000 Å
9000 Å
15000 Å

Discuss Question

Answer: Option A. -> 4000 Å
:
A

$The Refractive Index Of A Certain Glass Is 1.5 For Light Who...$

Question 8.

The refractive index of a piece of transparent quartz is the greatest for
[MP PET 1985, 94]

Red light
Violet light
Green light
Yellow light

Discuss Question

Answer: Option B. -> Violet light
:
B

$The Refractive Index Of A Piece Of Transparent Quartz Is The...$

Question 9.

On a glass plate a light wave is incident at an angle of $60^{\circ}$ . If the reflected and the refracted waves are mutually perpendicular, the refractive index of material is

$\frac{\sqrt{3}}{2}$
$\sqrt{3}$
$\frac{3}{2}$
$\frac{1}{\sqrt{3}}$

Discuss Question

Answer: Option B. ->

\sqrt{3}

:
B
From figure

r = 30^{\circ}

∴ μ = \frac{s i n i}{s i n r} = \frac{s i n 60^{\circ}}{s i n 30^{\circ}} = \sqrt{3}

On A Glass Plate A Light Wave Is Incident At An Angle Of 60�...

Question 10.

Velocity of light in glass whose refractive index with respect to air is 1.5 is $2 \times 10^{8} m s^{- 1}$ and in certain liquid the velocity of light found to be $2.50 \times 10^{8} m s^{- 1}$ .The refractive index of the liquid
with respect to air is