Refraction

Q.

A ray of light travelling in air enters obliquely into water. Does the ray of light bend towards the normal or away from the normal? Why?

Q. Define absolute refractive index of a medium and relative refractive index.

Q. If the refractive index of a material of equilateral prism is $\sqrt{3}$, then angle of minimum deviation of the prism is

1. ${30}^{\circ }$
2. ${45}^{\circ }$
3. ${60}^{\circ }$
4. ${75}^{\circ }$

Q.

Light travels through a glass plate of thickness $t$ and refractive index $n$. If $c$ is the velocity of light in vacuum, then the time taken by light to travel the thickness of the plate will be:

1. $\frac{nt}{c}$

2. $\frac{t}{nc}$

3. $\frac{tc}{n}$

4. $\frac{c}{nt}$

Q.

The angle of minimum deviation for a prism of refractive index $1.5$ is equal to the angle of the prism. The angle of the prism is (cos 41° = 0.75)

1. 62°

2. 41°

3. 82°

4. 31°

Q. Prism angle and refractive index respectively for a prism are ${60}^{\circ }$ and 1.414. Angle of minimum deviation will be

1. ${15}^{\circ }$
2. ${30}^{\circ }$
3. ${45}^{\circ }$
4. ${60}^{\circ }$

Q.

Refractive index of diamond is 2.42. Calculate the speed of light in diamond.

Q. A ray of light is incident on a glass prism at an angle of 24°. The refracting angles at the two surfaces are respectively 20° and 25°. If the angle of emergence is 30°, the total deviation produced by the prism is

1. 40°
2. 9°
3. 20°
4. 50°

Q. Question 12
Why does the Sun appear reddish early in the morning?

Q. Angle of minimum deviation is equal to the angle of prism A of an equilateral glass prism. The angle of incidence at which minimum deviation will be obtained is ${60}^{\circ }$.

1. True
2. False

Q.

Define lateral displacement.

Q.

Why do the stars twinkle but planets don't?

Q.

Describe the phenomenon behind the twinkling of star

Q.

(a) Explain why, a stick half immersed in water appears to be bent at the surface. Draw a labelled diagram to illustrate your answer. (b) A coin in a glass tumbler appears to rise as the glass tumbler is slowly filled with water. Name the phenomenon responsible for this effect.

Q.

Which of the following statements is correct regarding the propagation of light of different colors of white light in the air?

1. Red light moves fastest

2. Blue light moves faster than green light

3. All the colours of the white light move with the same speed

4. Yellow light moves with the mean speed as that of the red and the violet light

Q.

Which of the following correctly represents graphical relation between sine of angle of incidence (i) and sine of angle of refraction (r)?

1. 

2. 

3. 

4. 

Q. What is total internal reflection and mirage?

Q.

Mirage is caused due to

Q.

An object is immersed in a fluid. In order that the object becomes invisible, it should

1. absorb all light falling on it

2. behave as a perfect reflector

3. have refractive index exactly matching with that of the surrounding fluid

4. have refractive index one

Q. Differentiate between focus of a concave mirror and a convex mirror?

Q.

What is the recombination of the spectrum of white light?

Q.

Water in a pond appears to be only three - quarter of its actual depth. What property of light is responsible for this observation?

1. Reflection of light

2. Both A and B

3. Dispersion

4. Refraction of light

Q.

If a ray of light goes from a rarer medium to a denser medium, will it bend towards the normal or away from it?

Q. When white light passes through a prism, colour light bends the least.

1. red
2. blue
3. violet
4. orange

Q.

We can burn a piece of paper by focussing the sunrays by using a particular type of lens. Name the type of lens used for this purpose.

1. Convex and Concave lens

2. Plano-concave lens

3. Convex lens

4. Concave Lens

Q.

When a light ray passes from air into glass, what happens to its speed ? Draw a diagram to show which way the ray of light bends.

Q.

When a ray of light passes from air into glass, is the angle of refraction greater than or less than the angle of incidence?

Q.

If a ray of light goes from a denser medium to a rarer medium, will it bend towards the normal or away from the normal ?

Q. What is the cause of atmospheric refraction?

Q.

The speed of light in a denser medium is more than in a rarer medium.

1. True
2. False