Question

focus of a concave lens is 25 cm then its power is​

Answer 1

$hey \: mate \:$

$focal \: length {f} = - 25cm$

$power = 1 \div f(m)$

$= 100 \div f(cm)$

$= 100 \div - 25$

$=- 4d$

-4 D is the power..

Hope it helps you ☺️✌️✌️

Answer 2

I guess this is the answer..