Question

A converging lens of focal length 40 cm has a power of ______.

Options

• +2.50 D

• +2.00 D

• +2.40 D

• +2.60 D

Answer 1

A converging lens of focal length 40 cm has a power of +2.50 D.

Explanation:

A converging lens has positive power.

Converting 40 cm to 0.40 m.

Using $$\text{P} = \dfrac{1}{f}$$

$$= \dfrac{1}{0.40}$$

= +2.50 D