Question

the radius of curvature of a concave mirror is 18cm what is the focal length​

Answer 1

$\huge{\mathcal{\blue{\underline{Answer}}}}$

Radius of curvature = 2(focal length)

18cm=2(focal length)

Focal length :

$\huge{\mathcal{\blue{\underline{9cm}}}}$

Answer 2

Answer:

Radius of curvature = 18

Focal length = 1/2 ( radius of curvature)

= 1/2× 18

= 9 cm