Page 64 - NUMINO Challenge_B2

Basic Concepts Angles of Incidence and Reflection

Draw a line perpendicular to the surface from which light is being reflected.
The angle between the perpendicular line and the ray of light is called the
angle of incidence. The angle between the perpendicular line and the ray of
light being reflected is called the angle of reflection. The angle of incidence
and the angle of reflection are always equal to each other.

Vertical line

Ray of light Reflected light

Angle of Angle of
incidence reflection

Object

Example Two lasers are fired between two mirrors that are parallel to each
other. Find the measure of angle A.

Mirror

40

A
60

Mirror

Class Notes

Draw perpendicular lines at the points where the
laser hits the mirrors. In the 60° angle, the angles

of incidence and reflection are both and the 30 30
A
30 30

colored angle is .

The line connecting the points where the two lasers cross is parallel to both mirrors. The

upper part of angle A is a(n) 40
A
of the colored angle and the lower part of angle A

is a(n) to the 40° angle.

Therefore, angle A is .

Shapes 61