Question

The power of a lens is -2.0 diopters .what is it's focal length?what is the nature of this lens.?

Answer 1

Power of a lens = 1 / focal length

-2.0 = 100 / f(cm)

f = 100 / -2.0

Focal length of the lens = -50 cm

Since, the focal length is negative the lens is a "Concave lens".

Hope this helps you....