Question

A biconcave lens of power P vertically splits into two identical plano concave parts. The power of each part will be ______.

Options

• 2P

• P/2

• P

• `P//sqrt 2`

Answer 1

A biconcave lens of power P vertically splits into two identical plano concave parts. The power of each part will be P/2.

Explanation:

The power of a lens depends on the curvature of its two surfaces. When a symmetric biconcave lens of power P is split vertically into two identical plano-concave lenses, each part has only one curved surface (the other surface becomes plane). Hence, its power becomes half of the original lens, i.e., P/2.