Question

A lens has a power -2.5 D what is the focal length​

Answer 1

Answer:

Simplify 3(x - 6) - 4(x + 3)

Explanation:

Answer 2

Answer:

The power of a lens is defined as the reciprocal of the focal length. Lens power is measured in dioptres (D). Converging (convex ) lenses have positive focal lengths, so they also have positive power values. Diverging (concave ) lenses have negative focal lengths, so they also have negative power values

We know that power of lens is P= 1/f

P=-25D

So −25= 1/f

f=−.04m=−4cm

The power of this lens has minus sign, so it is a concave lens.