Question

Find the focal lenth of lens of power -2.0 D.what type of lens is this ?

Answer 1

Answer:

-0.5

Explanation:

P=1/F

F=1/P

=1/-2

=-0.5

focal length is negative .So lens is concave.

Answer 2

Explanation:

Power of lens, P= 1/f

P= -2D

f= -1/2 = -0.5 m

A concave lens has a negative focal length. Hence, it is a concave lens.