Question

If a converging lens of 5 D and diverging lens of power 2.5 D are placed

together, what is the power of combined lens?​

Answer 1

Given:-

• Power of converging lens (P¹) = +5D

• Power of diverging lens (P²) = -2.5D

To Find:-

• Power of combined lens (P).

Solution:-

The Power of a lens is defined as the reciprocal of its focal length.

As we know that the power of combined lens is

→ P = P¹ + P²

Substitute the value we get

→ P = 5 + (-2.5)

→ P = 5-2.5

→ P = 2.5D

∴ The Power of the combined lens is 2.5 D.