The distance of a lightbulb from a large plane mirror is
twice the distance of a person from the plane mirror. Light
from the bulb reaches the person by two paths. It travels to
the mirror at an angle of incidence &, and reflects from
the mirror to the person. It also travels directly to the
person without reflecting off the mirror. The total distance
traveled by the light in the first case is twice the distance
traveled by the light in the second case. Find the value of
the angle &.