An object 60cm from a lens gives a virtual image at a distance of 20cm in front of the lens. What is the focal length of the lens? Is the lens converging or diverging? Give reasons for your answer.

An object is placed between infinity and the pole of a convex mirror. Draw a ray diagram and also state the position, the relative size and the nature of the image formed.

The image of a candle flame formed by a lens is obtained on a screen placed on the other side of the lens. If the image is three times the size of the flame and the distance between lens and image is 80cm, at what distance should the candle be placed from the lens? What is the nature of the image at a distance of 80cm and the lens?

Give two circumstances in which a concave mirror can form a magnified image of an object placed in
front of it. Illustrate your answer by drawing labelled ray diagrams for both.

Two lenses have powers of (i) +2D and (ii) -4D. What is the nature and focal length of each lens?

The filament of a lamp is 80cm from a screen and a converging lens forms an image of it on a screen, magnified three times. Find the distance of the lens from the filament and the focal length of the lens.

Define principal axis, principal focus and focal length of a convex lens.

A diverging mirror of radius of curvature 40cm forms an image which is half the height of the object. Find the object and image positions.

An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed, so that a sharp focussed image can be obtained? Find the size and the nature of the image.