Lesson 3 10.2 Properties of Light and Reflection P.411-413. Today we will learn: A bout reflection. How to predict the location of an object using rays. How to draw a ray diagram for light reflecting off a smooth surface. SUCCESS CRITERIA I will be successful if I can
I will be successful if I can
Light travels in a straight line as long as it is moving through the same medium.
REFLECTION: The change in direction of a light ray when it bounces off a surface.
MEDIUM: The substance through which light travels.
RAY: A straight line with an arrowhead that shows the direction in which light waves are travelling.
Ray diagrams can be used to show how the size of the shadow depends on the objects distance from the light source.
Normal: Dashed line drawn perpendicular to the mirror at point of reflection.
Incident Ray: The incoming Ray of light from a light source towards a surface.
Reflected Ray: The outgoing Ray of light. Begins at the point where the incident ray and normal meet.
Angle of Incidence: The angle between the incident ray and the normal. (i)
Angle of Reflection: The angle between the normal and the reflected ray. (r)
Consider the diagram.
Which one of the angles (A, B, C, or D) is the angle of incidence? ______
Which one of the angles is the angle of reflection? ______
A ray of light is incident towards a plane mirror at an angle of 30 degrees with the mirror surface. Determine the angle of reflection.
90 – 30 = 60 degrees
Law of reflection states:
Angle of incidence = Angle of reflection
⦟ i = ⦟ r
Therefore, the angle of reflection will be 60°
A ray of light is approaching a set of three mirrors as shown in the diagram. The light ray is approaching the first mirror at an angle of 45-degrees with the mirror surface. Trace the path of the light ray as it bounces off the mirror. Continue tracing the ray until it finally exits from the mirror system.
How many times will the ray reflect before it finally exits?