Question

The power of lens is +2.5D.The focal lenght and the nature of lenght and the nature of lens

Answer 1

heya friend,

We know .
          Power P = 1/f
                 therefore: f = 1/P
                   
                 f = 100/2.5 = 40cm

Here, f = 40cm which is positive, it means the lens is a convex lens.

ANS :- FOCAL LENGTH=40cm
 LENS=CONVEX


hope this helps!!

Answer 2

focus length is equal to .4 meter