Question

a ray parallel to principle axis is incident at 30 degrees from normal on a concave mirror having radius of curvature r. the point on principle axis where rays are focussed is q such that pq is (where p is pole)

Answer 1

Answer:

The answer is $\frac{R}{2}$

Explanation:

We know parallel rays to principal axis focus at F, F = R/2

Hence, PQ is f = R/2