Question

power of a lens is_4D,then it's focal length is?​

Answer 1

Answer:

the focal length is expressed in metres, the power of a lens is the reciprocal of the focal length.

It is given that the power of a lens is 4 dioptre.

⇒ The focal length is 14 m =25

Answer 2

Answer:

0.25 m

Explanation:

Power of Lens = 4 D

$P = \frac{1}{F} \\ \implies\frac{1}{4} = F \\ \implies F = 0.25 \: m$