The surface of a concave mirror is pointed towards the sun. Light from the sun hits the mirror and converges to a point. How far is this converging point from the mirror's surface if the radius of curvature of the mirror is 150cm.
If the radius of the curvature is 150 cm, its focal length is,
f = R/2 = 150/2 = 75 cm
Light rays coming from the infinity converges at the focus ( 75 cm from the pole of the mirror ) of the mirror.