Question

Sunlight is incident on a concave mirror, parallel to its principal axis. The image is formed at a distance of 12 cm from the pole.
Find the radius of curvature of the mirror.

Answer 1

sun rays is incident in concave mirror, parallel to its principal axis , then light converge on a fixed point of concave mirror , that point is nammed as FOCUS.
hence, image formed at F ,
so, f = 12 cm

actually , concept is here, when rays of light comes from infinite , it converge on a fixed point on principal axis of concave mirror , e.g Focus .

now, we know
radius of curvature = 2 × focus
= 2 × 12 = 24 cm

but mirror is concave so,
sign of radius of curvature and focus is negative ,
hence R = -24 cm

Answer 2

Answer:

sun rays is incident in concave mirror, parallel to its principal axis , then light converge on a fixed point of concave mirror , that point is nammed as FOCUS.

hence, image formed at F ,

so, f = 12 cm

actually , concept is here, when rays of light comes from infinite , it converge on a fixed point on principal axis of concave mirror , e.g Focus .

now, we know

radius of curvature = 2 × focus

= 2 × 12 = 24 cm

but mirror is concave so,

sign of radius of curvature and focus is negative ,

hence R = -24 cm

Explanation: