Refraction through Glass Slab

Q. A ray of light is incident at the glass-water interface at an angle i = 41.8°. It emerges finally parallel to the surface of the water. What would be the value of the refractive index of the given glass? (Given: refractive index of water = 4/3)


(use the value: sin 41.8° ≈ 0.66)

[0.8 mark]

1. 7/3
2. 1.5
3. 4/3
4. 1

Q. The refractive index of glass is $1.5$. From a point P inside a glass slab, draw three rays PA, PB and PC incident on the glass-air surface making angles of incidence ${30}^{\circ }$, ${42}^{\circ }$ and ${60}^{\circ }$ respectively.
(a) In the diagram show the approximate direction of these rays as they emerge out of the slab.
(b) What is the angle of refraction for the ray PB.

Hint: $\sin \left({42}^{\circ }\right)=2/3$

Q.

The image formed by a plane mirror of an object is due to which phenomenon?

1. Refraction

2. Reflection

3. Diffusion

4. Scattering

Q. An air bubble is present in a glass $(\mu$ = 1.5) at a distance of $3\text{cm}$ from the curved convex surface of radius $5\text{cm}$. Position of the image of bubble is
($\mu$ is refraction index)

1. $1.67\text{cm}$
2. $2.5\text{cm}$
3. $3.8\text{cm}$
4. $6\text{cm}$

Q.

A man holding a lighted candle in front of thick glass mirror and viewing it obliquely sees a number of images of the candle. What is the origin of these multiple images?

Q. In the case of refraction of light in a rectangular glass slab, if $\text{i}$ is the angle of incidence and $\text{e}$ is the angle of emergence, then:

1. $\text{e}<\text{i}$
2. $\text{e}=\text{i}$
3. $\text{e}>\text{i}$
4. $\text{e}$ and $\text{i}$ are unrelated

Q. What is a screen ? and How the image formed by the plane mirror is behind it ?

Q.

A ray of light is incident on the plane surface of a transparent medium at an angle 60° with the normal. The angle of refraction is 30°. Calculate the refractive index of the transparent material. Give the equation of refractive index interms of real depth and apparent depth. [3 MARKS]

Q.

A plane mirror and an object approach each other with speeds of 5m/s and 10 m/s respectively. The speed of the image will be 20 $\frac{m}{sec}$.

1. True

2. False

Q.

The angle between the emergent ray and incident ray when the light goes from air to glass slab is___.

1. $0^{\circ }$

2. ${60}^{\circ }$

3. ${45}^{\circ }$

4. ${90}^{\circ }$

Q. When two light rays intersect with each other in a medium like glass or water, will they form an image ?

Q. Laws of refraction are valid for curved surfaces.

1. True
2. False

Q.

A point source of light O of a single color is seen through a rectangular glass slab PQRS. The paths of two rays, in and outside the slab, are shown in the given figure.

In the diagram, what is the position I of the source O, when seen through the surface RS?

1. Below 'O'

2. Same position as 'O'.

3. To the right of 'O'.

4. Above 'O'

Q. In the adjacent diagram, AO is a ray of light incident on a rectangular glass slab.

(a) Complete the path of the ray till it emerges out of the slab.
(b) In the diagram, mark the angle of incidence (i) and the angle of refraction (r) at the first interface. How is the refractive index of glass related to the angles i and r ?
(c) Mark angle of emergence by the letter e. How are the angles i and e related ?
(d) Which two rays are parallel to each other ?
(e) Indicate in the diagram the lateral displacement between the emergent ray and the incident ray. State one factor that affects the lateral displacement.

Q.

The diagram below shows a ray of white light PQ coming from an object P and incident on the surface of a thick glass plane mirror

How many images will be formed and which image will be the brightest image.

1. 4 images are formed and all images are equally bright

2. 2 images are formed and all images are equally bright

3. Infinite images are formed and 2^nd image is the brightest

4. Infinite images are formed and 1^st image is the brightest

Q. In the top view of a scenario (as shown in figure below), the image of the stone seen by observer 1, due to the plane mirror, is at C. Where does observer 2 see the image?

1. B
2. A
3. C
4. D

Q.

When a lighted candle is held in front of a thick plane glass mirror, several images can be seen, but the second image is the brightest.

1. True

2. False

Q.

Choose the correct ray diagram when a light falls normally on a surface separating two different media:

1. 

2. 

3. 

4. 

Q. What are the factors on which the lateral displacement (d) of light through a glass slab does not depend on?

1. The thickness of the glass slab
2. The angle of incidence
3. The refractive index of glass
4. The mass of the glass slab

Q. What happens to the ray of light when it passes from glass to air?

Q. The angle of minimum deviation from a prism is ${37}^{\circ }.$ If the angle of prism is ${53}^{\circ },$ find the refractive index of the material fo the prism.

1. 1.95
2. 1.72
3. 1.58
4. 1.63

Q. Multiple images form in a thick plate. How many images are formed in this case?

1. 1
2. 2
3. Multiple
4. None

Q.

A ray of light is incident on a medium at an angle 60°. The angle of refraction is different for different mediums for an angle of incidence = 60${}^{\circ }$.

In which medium is the speed of light lowest?

1. 1

2. 3

3. 2

4. same in all

Q.

a) A ray of light travelling in the air falls on the surface of a glass slab at an angle 45° with the normal. The refractive index of glass is 1.5. Calculate the angle of refraction.
b) A point object is placed at a distance of 18 cm from a convex lens on its principal axis. Its image is formed on the other side of the lens at 27 cm. Calculate the focal length of the lens. [5 MARKS]

Q. Images formed by multiple reflections become

1. Brighter
2. Fainter
3. No effect
4. None

Q. What role does the opposite parallel surfaces of a glass slab play in lateral shift of light passing through them?

Q. Convex mirrors produce virtual images only.

1. False
2. True

Q. A ray of light is incident at an angle of incidence ${45}^{\circ }$ on the face of a prism having angle of the prism ${30}^{\circ }$. The refracted ray does not change its direction as it crosses the other face and emerges out of the prism. Find:
(a) the refractive index of the material of the prism and
(b) the angle of deviation.

Q. State the relation between the critical angle and the absolute refractive index of a medium.

Q. Laws of refraction are not valid for curved surfaces.

1. True
2. False