Unit 3:Light

 Terms: Curved mirror- can be thought of as a large number of plane mirrors all having slightly different angles. The laws of reflection still apply Converging mirror- has a concave reflecting surface Diverging mirror- has a convex reflecting surface

 You try: Look at a spoon Which side is convex (diverging) and which is concave (converging)?  How does you image change as you change the position of your spoon (ie bring it closer to your face)  How does the image change as you flip the spoon over and look into the other side of the spoon?  In jot form write down your answers

 Grab a rive ray box and ensure that the light is shining through the three slits  Focus the light on a concave mirror  Focus the light on a convex mirror  What happens to the reflected light when it hits each of the lenses?  Draw the reflection from each mirror (add to the last answers) and hand this in

 Why is the mirror called diverging and converging mirrors?

 Vertex (V)- center of the mirror  Center of curvature (C)- center of spherical reflecting surface  Principle axis- passes through V+C  Radius of curvature (R)- distance from center of curvature to the mirror  Principle focus (F)- point on principle axis where incident rays converge to or diverge from

 Focal length (f)- distance between principle focus and the vertex; 2f= R (f is half the distance of R)

 Start by drawing the three critical rays; 1. Incident ray that is parallel to the principle axis is reflected through the principle focus

2. an incident ray passing through the principle focus is reflected parallel to the principle axis

 3. an incident ray passing through the center of curvature reflects along the same path

 Principle of reversibility- a light ray will follow an identical path in the opposite direction  The object is represented by an arrow, touching the principle axis  Critical rays are drawn from the tip of an object  Where the critical rays converge corresponds to the tip of the image

 Image characteristics: Type: Virtual Attitude: upright Magnification: smaller (m<+1) Position: located between V and F (unless object is right at the mirror surface)