We
have to prove that if a plane mirror is rotated through an angle
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Solution: Click For PDF Version Let M be the initial position of the mirror. Let the incident ray
make an angle
with the normal N to
M. By the law of
reflection from plane mirrors we note that the reflected ray
will be at angle
with respect to the normal N;
as shown in the figure.
Let the
mirror be rotated by an angle
|
,
the reflected beam is rotated through an angle
.
to
the new position of the mirror
has turned by angle
.
The incident ray
.
The angle that ray
.
Therefore, angle between
.
Thus we have proved that if a plane mirror is turned by an angle