The second law of refraction gives a relationship between the angle of incidence and the angle of refraction. This relationship was discovered by Snell experimentally, so the second law of refraction is called Snell’s law of refraction. According to Snell’s law of refraction of light: The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant, for the light of a given colour and for the given pair of media. If i is the angle of incidence and r is the angle of refraction, then sin i sin r = constant . This constant value is called the refractive index of the second medium with respect to the first.

Define power of a lens. What is its unit?

The power of a lens is a measure of the degree of convergence or divergence of light rays falling on it. The power of a lens is defined as the reciprocal of its focal length in metres. If P denotes the power of a lens and f denotes the focal length of the lens, the power is formulated as; P = 1 f ( in metres ) The SI unit of power of lens is dioptre ( D ).

E M B I B E

Eduwiser's CBSE PHYSICS FOR CLASS X>Chapter 4 - Light - Reflection and Refraction>EXERCISE>Q 8

HARD

10th CBSE

IMPORTANT

Earn 100

The radius of curvature of a dentist's mirror is $2.8 cm$ . If the dentist wants a four times magnified virtual image of a small dental cavity, how far should the mirror be placed from the cavity?

Important Questions on Light - Reflection and Refraction

MEDIUM

10th CBSE

IMPORTANT

Eduwiser's CBSE PHYSICS FOR CLASS X>Chapter 4 - Light - Reflection and Refraction>EXERCISE>Q 9

The focal length of a rear-view convex mirror of a car moving at a speed of

40 km / hr

is

1 m

. A bus is following the car at a distance of

4 m

with the same speed. What are the position and the nature of the image formed? Also find the size of the bus image relative to the actual size of the bus.

HARD

10th CBSE

IMPORTANT

Eduwiser's CBSE PHYSICS FOR CLASS X>Chapter 4 - Light - Reflection and Refraction>EXERCISE>Q 10

A security mirror in the car park of a building is

4 m

away from a Porsche car. If the mirror produced one-ninth magnification, calculate the radius of curvature of the mirror.

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE PHYSICS FOR CLASS X>Chapter 4 - Light - Reflection and Refraction>EXERCISE>Q 1

Define refraction of light.

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE PHYSICS FOR CLASS X>Chapter 4 - Light - Reflection and Refraction>EXERCISE>Q 2

Why does a ray of light bend when it travels from one medium into another?

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE PHYSICS FOR CLASS X>Chapter 4 - Light - Reflection and Refraction>EXERCISE>Q 3

A ray of light passing from medium

X

to medium

Y

bends away from the normal. Which of the two media is optically denser?

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE PHYSICS FOR CLASS X>Chapter 4 - Light - Reflection and Refraction>EXERCISE>Q 4

A ray of light is incident normally to the surface of a glass slab placed in air. Find the angle of incidence and the angle of refraction in this case.

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE PHYSICS FOR CLASS X>Chapter 4 - Light - Reflection and Refraction>EXERCISE>Q 5

What is Snell's law?

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE PHYSICS FOR CLASS X>Chapter 4 - Light - Reflection and Refraction>EXERCISE>Q 6

What is the relation between the angle of incidence and the angle of refraction for a pair of media?