If a laser strikes a mirror with an angle of incidence of 36°, what is the angle between the angle of incidence and angle of reflection?
Answers
If you measure the angle of incidence from the normal, the angle of reflection will also be
36
0
for a total of
72
0
However if the
36
0
you mention is the angle as measured from the plane of the mirror, then the angle of incidence (as measured from the normal) will be
90
0
−
36
0
=
54
0
and the total angle will be twice that
2
⋅
54
0
=
108
0
.
The normal is a line perpendicular to the surface of the mirror at the point where the incoming ray strikes. It is usual to measure the angles from the normal, as this makes calculations on curved mirrors a lot easier.
In those the normal is the line drawn from the centre of the sphere of which your (concave or convex) mirror is a part.
If a laser strikes a mirror with an angle of incidence of 36°, ... between the angle of incidence and angle of reflection