Question

find the power of the lens whose focal length is 25 cm​

Answer 1

Answer:

Explanation:

focal length in meters.

⇒25cm=0.25m

Now, substituting the value of focal length in the formula of power of lens we get

P=10.25m−1

⇒P=4m - 1

m−1 is also expressed as diopters or D

Thus, the power of the lens is +4D.

Answer 2

Answer:+4D

Explanation:

Here,

f=25cm=0.25m

Power=1/f

=1/0.25

=+4D

The power comes out to be +4D, and since it is positive the lens being used is a convex lens.