Question

if the power of lens is1d what is its focal length​

Answer 1

Explanation:

A dioptre (D) is a reciprocal metre of focal length if a lens. Focal length (f) is where the rays of light focus to after passing through the lens. So if f=1m then the power (F) of the lens would be 1\1 =1D. So if f=0.5m then F=1\0.5 = 2D.

Answer 2

Answer:

If the power is negative, then the lens is concave. If the power is positive, then the lens is convex. This case the given lens is concave and the length of focal is 1 metre