A plane mirror is mounted on a motor that rotates the mirror about an axis coincident with the mirror’s normal. A laser beam in air strikes the mirror at an angle of 50∘ to the normal. If the mirror is rotated by 60∘ about that normal, what happens to the direction of the reflected beam?
a) The reflected beam rotates by 60∘.
b) The direction of the reflected beam remains unchanged.
c) The reflected beam rotates by 120∘.
d) The reflected beam rotates by 30∘.