Define Snell's law of refraction. A ray of light is incident on a glass slab at an angle of incidence of 60°. If the angle of refraction be 32.7°, calculate the refractive index of glass. (Given: sin 60° = 0.866 and sin 30° = 0.5).

List the new Cartesian sign convention for reflection of light by spherical mirrors. Draw a diagram and apply these conventions for calculating the focal length and nature of a spherical mirror which forms 1/3 times magnified virtual image of an object placed 18 cm if front of it.

List the sign conventions for reflection of light by spherical mirror. Draw a diagram and apply these conventions in the determination of focal length of a spherical mirror which forms three times magnified real image of an object placed. 16 cm in front of it.

Draw a diagram to show how a converging lens held close to the eye acts as a magnifying glass. Why is it usual to choose a lens of short focal length for this purpose rather than one of long focal length?

State and explain the New Cartesian Sign Convention for spherical lenses.

What type of lens is shown in the diagram on the right ? What will happen to the parallel rays of light? Show by completing the ray diagram.

Your eye contains a convex lens. Why is it unwise to look at the sun?

A dentist uses a mirror in front of a decayed tooth at a distance of 4 cm from the tooth to get four times magnified image in the mirror. Use mirror formula to find the focal length and nature of the mirror used.