TIR in Prism

Q.

When light rays are incident on a prism at an angle of ${45}^{\circ }$, the minimum deviation is obtained. If the refractive index of the material of prism is $\sqrt{2}$ then the angle of the prism will be

1. 30°

2. 40°

3. 50°

4. 60°

Q.

A glass prism of refractive index 1.5 is immersed in water $(\mu =\frac{4}{3})$. A light beam incident normally on the face AB is totally reflected to reach the face BC if

1. $\frac{2}{3}<sin\theta <\frac{8}{9}$

2. $sin\theta >\frac{8}{9}$

3. $sin\theta \le \frac{2}{3}$

4. $cos\theta \ge \frac{8}{9}$

Q.

Mention one difference between the reflection of light from a plane mirror and total internal reflection of light from a prism.

Q.

Two plane mirrors are initially inclined at 30° and they are moved apart by 30° each time, till the angle between them becomes 120°. If an object is placed symmetrically between them then find the sum of all the images formed.

1. 20

2. 22

3. 21

4. 23

Q. Plane mirrors have zero power.

1. False
2. True

Q.

A prism $(\mu =1.5)$ has the refracting angle of 30°. The deviation of a monochromatic ray incident normally on its one surface will be (sin 48° 36' = 0.75), The angle of deviation is

1. 18° 36'

2. 22°1'

3. 20° 30'

4. 18°

Q.

In Fig. 4.67, a ray of light PQ is incident normally on the face AB of an equilateral glass prism. Complete the ray diagram showing its emergence into air after passing through the prism. Take critical angle for glass = ${42}^{\circ }$.

(a) Write the angles of incidence at the faces AB and AC of the prism.

(b) Name the phenomenon which the ray of light suffers at the face AB, AC and BC of the prism.

Q.

State one advantage of using a total reflecting prism as a reflector in place of a plane mirror.

Q.

Explain the following :
A crack in a window pane appears silvery.

Q. The refractive index of a prism is 2.This prism can have a maximum refracting angle of

1. ${90}^{\circ }$
2. ${60}^{\circ }$
3. ${30}^{\circ }$
4. ${45}^{\circ }$

Q.

Two advantages of using a right-angled prism as a reflector, rather than a plane

1. Image formed by prism is magnified as compared to that by a mirror

2. Image formed by prism is inverted as compared to that by a mirror

3. Image formed by prism is upright and diminished as compared to that by a mirror

4. Image formed by prism is sharper as compared to that by a mirror

Q.

State the law of reflection.

Q.

The difference between reflection of light from a plane mirror and total internal reflection of light from a prism is:

1. The image formed is diffused and shimmering with prism as compared to a plane mirror

2. The image formed is sharper with plane mirror as compared to a prism

3. The image formed is sharper with prism as compared to a plane mirror

4. The image formed is diffused and shimmering with plane mirror as compared to a prism

Q. A total reflecting right angled isosceles prism can be used to deviate a ray of light through:

1. 30°
2. 60°
3. 75°
4. 90°

Q.

Choose the right option for the brilliance of a diamond?

1. Total internal reflection

2. Reflection

3. Shape

4. Cutting

Q. Name a piece of apparatus other than plane mirror, which can be used to turn a ray of light through 90 degree ? Do I need to specify the type of prism used(the isosceles prism) ?

Q.

Show with the help of a diagram how a total reflecting prism can be used to turn a ray of light through ${90}^{\circ }$. Name one instrument in which such a prism is used.

Q. In an equilateral prism, if a ray is incident on the normal, the angle of the internally reflected ray deviates through .

1. ${30}^0$
2. ${90}^0$
3. ${60}^0$
4. ${45}^0$

Q.

A ray of light passes through a right-angled prism as shown in the given figure. The angle of incidence at the faces AC and BC are:

1. 0^o; 45^o

2. 45^o; 0^o

3. 90^o; 45^o

4. 45^o; 90^o

Q.

A total reflecting equilateral prism can be used to deviate a ray of light through:

(a) ${30}^{\circ }$ (b) ${60}^{\circ }$ (c) ${75}^{\circ }$ (d) ${90}^{\circ }$

Q.

A prism used in a Binocular to invert image. In such a case:

1. The light is turned by 90⁰ by making light undergo TIR twice using a right angled isosceles prism.

2. The light is turned by 180⁰ by making light undergo TIR once using a right angled isosceles prism.

3. The light is turned by 90⁰ by making light undergo TIR once using a right angled isosceles prism.

4. The light is turned by 180⁰ by making light undergo TIR twice using a right angled isosceles prism.

5. The light is turned by 360⁰ by making light undergo TIR twice using a right angled isosceles prism.

Q.

What is a total reflecting prism? State three actions that it can produce. Draw a diagram to show one such action of the total reflecting prism.

Q.

Trace the path of a ray of light through a triangular glass prism. Also, label the diagram.

Q.

What device other than a plane mirror can be used to turn a ray of light through ${180}^{\circ }$ ? Draw a diagram in support of your answer. Name an instrument in which this device is used.

Q.

When light strikes the surface of a non-metallic material it bounces off in all directions due to ___

1. refraction

2. multiple reflections

3. regular reflection

4. reflection

Q. What is the minimum value of the refractive index for a ${90}^{\circ }–{45}^{\circ }–{45}^{\circ }$ prism
which is used to deviate a beam through ${90}^{\circ }$ by total internal reflection ?

1. $\sqrt{3}$
2. $\frac{3}{2}$
3. $\sqrt{2}$
4. $\frac{5}{3}$

Q. A parallel beam of light is incident from air at an angle $\alpha$ on the side $PQ$ of a right angles triangular prism of refractive index $n=\sqrt{2}.$ Light undergoes total internal reflection in the prism at the face $PR$ when $\alpha$ has a minimum value of ${45}^o.$ The angle $\theta$ of the prism is

1. ${15}^o$
2. ${22.5}^o$
3. ${30}^o$
4. ${45}^o$

Q. The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42$°$. Complete the path of the ray PQ till it emerges out of the block [Write necessary angles].

Q.

A torch light kept at a depth h below the surface of an ocean (n = 4/3) facing upward is turned ON. Determine the illuminated surface area at the free surface of ocean.

1. $\frac{9\pi h^2}{16}$
2. $\frac{9\pi h^2}{7}$
3. $\frac{3\pi h^2}{4}$
4. $\frac{\pi h^2}{3}$

Q.

A total reflecting right angled isosceles prism can be used to deviate a ray of light through :

(a) ${30}^{\circ }$ (b) ${60}^{\circ }$ (c) ${75}^{\circ }$ (d) ${90}^{\circ }$