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?
If you measure the angle of incidence from the normal, the angle of reflection will also be
However if the
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.