Question

Find the power of a concave lens of focal length 2 m.

Answer 1

P = 1/f(in m) = 1/-2 = -0.5 D

Answer 2

$\large \underline{ \underline{ \sf \: Solution : \: \: \: }}$

Given ,

Focal length = - 2 m

We know that ,

$\large\sf \fbox{ \fbox{Power = \frac{1}{ \: focal \: length \: } }}$

$\to \sf Power = - \frac{1}{2} \\ \\ \to \sf Power = - 0.5 \: \: D$

Hence , - 0.5 D is the power of concave lens