Question

power of lens is +5D . find focal length

Answer 1

Hey User !!!

P = + 5 D

Power = reciprocal of focal length in metres

P = 1/f

f = 1/P

f = 1/5 = 0.2 m

0.2m to cm

0.2 × 100 = 20 cm

Answer 2

Answer:

The focal length of the lens is 20 cm.

Explanation:

Given that,

The power of the lens = +5 D

We know that,

The power of the lens is the reciprocal of the focal length of the lens.

$P=\dfrac{1}{f}$

$5=\dfrac{1}{f}$

$f=\dfrac{1}{5}$

$f=0.2\ m$

$f=20 cm$

This is the focal length of the convex lens.

Hence, The focal length of the lens is 20 cm.