A convex lens ‘A’ of focal length 20 cm and a concave lens ‘B’ of focal length 5 cm are kept along the same axis with a distance ‘d’ between them. If a parallel beam of light falling on ‘A’ leaves ‘B’ as a parallel beam, then the distance ‘d’ in cm will be:

Which of the following pair is INCORRECT for some transparent media with respect toair? (may consider the most approximate value)

Find the value of 'X' and 'h' in the following diagram.

A coin of diameter 10 cm is placed at a distance 3.5 f from the pole of a concave mirror of focal length f. The linear magnification and the diameter of the image are:

Which of the following pair is INCORRECT for some transparent media with respect toair? (may consider the most approximate value)