Question

The radius of curvature of concave mirror is 12 cm.
Then, the focal length will be
(a) 12 cm
(b) 6 cm
(c) - 24 cm
(d) - 6 cm​

Answer 1

Answer: it is -6cm

Explanation: The focal length of a concave mirror is always negative as f is in front of the mirror

Therefore, 2f=-R

-R/2=f

-12/2=f = -6

Hope this would help you :)