Question

if two lens of focal lengths 10 cm and 20 cm are kept in contact, find the power of combination​

Answer 1

Explanation:

So, the effective power of combination is 30 cm.

Answer 2

Explanation:

Given that,

Focal length of lens 1,

Focal length of lens 2,

The power of lens 1 will be :

The power of lens 2 will be :

The effective power of the combination is simply sum of powers of individual powers as :

P = 0.3 m

or

P = 30 cm

So, the effective power of combination is 30 cm. Hence, this is the required solution