Question

When a parallel beam of paraxial light strikes a concave spherical mirror, the reflected rays:

Options

• converge to a single point

• appear to diverge from a single point

• continue travelling parallel to one another

• scatter randomly in all directions

Answer 1

A concave mirror causes a parallel paraxial beam to converge to a single point after reflection — this point is the Principal Focus. The reflected rays do not scatter randomly; they meet at the focus in front of the mirror.