Question

find the focal length in centimetre of a lens of power - 2D?

Answer 1

We know that P=1/f(in metres)

-2D=1/f

f=1/-2

f=-0.5m

f=-50cm

Therefore, the focal length is -50 cm. It is a concave lens

Answer 2

*Hello* mate your answer is in the above picture.

Hope this helps you