Question

How does a convex lens act as a ‘converging lens’?

Answer 1

Convex lens may be considered as being made of a large number of prisms, such that in its upper half, prisms have their bases downwards and in its lower half, the prisms have their bases upwards, Due to this, the upper half part deviates the rays of light downwards and the lower half deviates the rays of light upwards while the central part of the lens acts as a glass block allowing the light to pass undeviated. So, any parallel beam of light incident on it converges to a point F.