With the help of a labelled diagram, explain how a concave lens diverges a beam of parallel light rays.

If the magnification of a body of size 1m is 2, what is the size of the image?

Write down a formula for the magnification produced by a concave mirror.

1. In terms of height of object and height of image.
2. In terms of object distance and image distance.

A convex lens is immersed in a liquid of refractive index greater than that of glass. How will the nature of lens change?

At what distance from a converging lens of focal length 12cm must an object be placed in order that an image of magnification 1 will be produced?

Draw and complete the following diagrams to show what happens to the beams of light as they enter the glass block and then leave it:

Where must the object be placed for the image formed by a converging lens to be:

1. Real, inverted and smaller than the object?
2. Real, inverted and same size as the object?
3. Real, inverted and larger than the object?
4. Virtual, upright and larger than the object?

Draw a ray diagram showing how a concave mirror can be used to produce a real, inverted and diminished image of an object.

Refractive indices of four media A, B, C and D are given below:

Medium	Refractive index
A B C D	1.33 1.44 1.52 1.65

In which of these four media is the speed of light:

1. Maximum, and
2. Minimum?