Question

Two lenses have power of
(a) +2D
(b) -4D​

Answer 1

Answer:

I think+2D is the answer

Answer 2

Answer:

a. Power = 2D

But, Power = 1 / Focal length, f

      2 = 1/f

f = 1/2

f = 0.5

b. Power = -4D

But, Power = 1/ Focal  ,f

-4 = 1/f

f = -1/4

f = -0.25  

Explanation:

Hope it helps you buddy.... :)