Question

what is the focal length of a lens having power -4 dioptrer

Answer 1

Heya mate here is your answer:

✍Focal length = 1/power of lens.

✍so, Focal length = 1/(-4)

=0.25 m✔

Answer 2

Answer:

The focal length of the lens having power -4 diopter is -0.25.

By the formula, D=1/f

-4=1/f

f=1/-4

f=-0.25