The diagrams show the appearance of a fork when placed in front of and close to two mirrors A and B, turn by turn.

1. Which mirror is convex.
2. Which mirror is concave.

Give reasons for your choice.

When an object is placed at a distance of 15cm from a concave mirror, its image is formed at 10cm in front of the mirror. Calculate the focal length of the mirror.

What is the position of the image when an object is placed at a distance of 20cm from a concave mirror of focal length 20cm?

When an object is placed at a distance of 36cm from a convex lens, an image of the same size as the object is formed. What will be the nature of image formed when the object is placed at a distance of:

1. 10cm from the lens?
2. 20cm from the lens?

State and explain the laws of refraction of light with the help of a labelled diagram.

Why do we prefer a convex mirror as a rear-view mirror in vehicles?

With the help of a ray diagram, determine the position, nature and size of the image formed of an object placed at the centre of curvature of a concave mirror.

The lens A produces a magnification of, -0.6 whereas lens B produces a magnification of +0.6:

1. What is the nature of lens A?
2. What is the nature of lens B?

A communications satellite in orbit sends a parallel beam of signals down to earth. If these signals obey the same laws of reflection as light and are to be focussed onto a small receiving aerial, what should be the best shape of the metal 'dish' used to collect them?

Draw ray diagrams showing the image formation by a concave lens when an object is placed:Between focus and twice the focal length of the lens.