Question

If the focal length of a concave lens is 2 m, then the power of the lens is

Answer 1

Answer:

0.5

Explanation:

P = 1/f

Answer 2

ANSWER:

The power of the lens is -0.5D

EXPLANATION:    

The dioptre is used to measure lens power and is used as a unit. The dioptre is known as the inversely proportional to the "focal length" of the lens, or D = 1/f

Therefore, the power of the lens is reciprocal to the "focal length" of the concave lens.

$\text { Power }=\frac{1}{f}$

The focal length of the concave lens is given as 2 m

The power of the concave lens is calculated as

$\text { Power }=\frac{1}{-2(\text { concave })}$

The power of the lens is -0.5D