Refraction of Light through a Prism

Q.

When a white light ray falls on a prism, the ray at its first surface suffers :

(a) no refraction

(b) only dispersion

(c) only deviation

(d) both deviation and dispersion.

Q.

An object is viewed through a glass prism with its vertex pointing upwards. Draw a ray diagram to show the formation of its image seen by the observer.

Q.

Why do different colors deviate at different angles when passing through a prism?

Q.

State whether the following statement is 'true' or 'false' :

The deviation produced by a prism is independent of the angle of incidence and is the same for all colours of light.

Q.

A ray of light suffers refraction through an equilateral prism. The deviation produced by the prism does not depend on the :

(a) angle of incidence (b) colour of light

(a) material of prism (b) size of prism

Q.

What is a prism? With the help of a diagram of a principal section of a prism, indicate its refracting surfaces, refracting angle and base.

Q.

In refraction of light through a prism, the light ray:

(a) suffers refraction only at one face of the prism

(b) emerges out from the prism in a direction parallel to the incident ray

(c) bends at both the surfaces of prism towards its base

(d) bends at both the surfaces of prism opposite to its base

Q.

Statement 1: When white light ray passes through a prism, it disperses into seven different colours, and this phenomenon is called dispersion.

Statement 2: In a refracting media, lights of different colour travel at different speed.

1. Statement 1 and 2 are correct but statement 2 is not the correct reason of statement 1.

2. Statement 1 and 2 are correct and statement 2 is the correct reason for statement 1.

3. Both statements are wrong.

4. Statement 1 is correct but statement 2 is incorrect.

Q.

• "The angle between the 2 lateral faces of the prism is called angle of the prism". What are the two lateral faces ?

Q. A point object is kept at the focus of a convex lens

1. We will get a parallel beam of light
2. We will get a convergent beam of light
3. We will get a divergent beam of light
4. Can't comment

Q.

When a ray of light is passed through a hollow glass prism, it does not give a spectrum. Explain why?

Q.

Light rays get refracted ______ when they pass from air to glass prism.

1. towards the normal

2. along the normal

3. along the air-glass interface

4. away from the normal

Q.

A graph is plotted between the angle of deviation $\delta$ and angle of incidence $i$ for a prism. The nearly correct graph is

Q. As light rays pass from air into a glass prism, are they refracted towards or away from the normal ?

Q. A light ray of yellow color is incident on an equilateral glass prism at an angle of incidence equal to 48${}^{\circ }$ and suffers minimum deviation by an angle of 36${}^{\circ }$. (i) What will be the angle of emergence? (ii) If the angle of incidence is changed to (a) 30${}^{\circ }$, (b) 60${}^{\circ }$, state in each case whether the angle of deviation will be equal to, less than or more than 36${}^{\circ }$?[3 marks]

Q.

Write some terms related to the prism.

Q. The line along which the two refracting faces meet is called the ___ of the prism.

1. Refracting edge
2. Refracting angle
3. Principal section
4. None of these

Q.

(a) A beam of monochromatic light undergoes minimum deviation through an equiangular prism, how does the beam pass through the prism, with respect to its base ?

(b) If white light is used in same way as in part (a) above, what change do you expect in the emergent beam ?

(c) What conclusion do you draw about the nature of white light in part (b) ?

Q.

The refractive index of air with respect to glass is expressed as ${}_g{\mu }_a$​ = $\frac{\sin i}{\sin r}$ if ∠ r = ${90}^{\circ }$​. What is the corresponding ∠i called?

1. None of these

2. ∠i > ∠i_c

3. ∠i = ∠i_c

4. ∠i < ∠i_c

Q.

How is dispersed white light recomposed? Draw a neat labelled diagram to explain. [5 MARKS]

Q. Choose the correct statement for a rectangular glass slab?

1. The emergent ray is parallel to the incident ray.
2. The emergent ray coincides with the incident ray.
3. The emergent ray is perpendicular to the incident ray
4. The emergent ray is inclined to the incident ray.

Q. In the formation of spectrum of white light by a prism :
(i) which colour is devitated least ?
(ii) which colour is deviated most ?

Q.

Draw a ray diagram to show the refraction of light through a glass prism.

On the diagram mark a) Incident angle b) emergent ray c) angle of deviation. [3 MARKS]

Q. What is the speed of light in air?

Q. Velocity of light in glass is $2\times {10}^{8}m{s}^{-1}$ and in air is $3\times {10}^{8}m{s}^{-1}$. If the ray passes through glass to air, calculate the value of critical angle.

1. ${40}^{\circ }$
2. ${42}^{\circ }$
3. ${45}^{\circ }$
4. ${50}^{\circ }$

Q.
A light ray enters a prism through the side PR. PQR is a cross section of the prism. The emergent ray lies along the boundary OQ. ∠P = 90° and PQ = PR. The ray diagram has been given.

iii. If we immerse the whole system fully under water (refractive index = 1.3), what will happen?

[1 mark]

1. The ray follows the OQ path.
2. We observe a total internal reflection.
3. The angle of emergence > ∠BOC
4. The angle of emergence < ∠BOC

Q. The phenomenon due to which white light splits into seven colours on passing through a prism is called _________

1. reflection
2. refraction
3. all the above
4. dispersion

Q.

The phenomenon of light splitting into its constituent colours is known as ________ of light.

Q. a. Draw the given diagram and label the following in the diagram.
i) Incident ray
ii) Refracted ray
iii) Emergent ray
iv) Angle of refraction
v) Angle of deviation
vi) Angle of emergence
b. The refractive index of diamond is 2.42. What is the meaning of this statement in relation to the speed of light?

Q. As light rays emerge from a glass prism into air, are they refracted towards or away from the normal ?