1. Reflection

2. When a wave changes media, some of it is reflected back.
The amount of reflection depends on how different the media are.

4. Angle of Incidence = Angle of Reflection
Light reflected from a plane (flat) mirror follows the Law of Reflection: These angles are measured from the normal, a line perpendicular to the mirror.
Angle of Incidence = Angle of Reflection
Ɵi = Ɵr

5. Questions: Why can you not see yourself in all flat surfaces
Questions: Why can you not see yourself in all flat surfaces? The paper is rough and gives irregular reflections.

6. Ray Diagrams
When you look at an image in a plane mirror it is:
The same size.
The same distance behind the mirror as you are in front of it.
Right side up and laterally inverted.
Also, the reflected light has the same speed, wavelength and frequency as the incident light.

7. When drawing ray diagrams we draw two rays of light coming from the object, reflecting and then heading to the observer.

8. Questions: What minimum length of mirror do you need to obtain a full length view of yourself? You need a mirror half your height.

9. Curved Mirrors Concave mirrors are curved (“caved”) inwards
Convex mirrors are curved outwards

10. Since the surfaces are curved, the normal is different at different points.

11. Concave Mirrors
Principle axis: straight line perpendicular to the mirror Centre of curvature (C): the point that represents the center of the sphere Focal point (F): point where all of the reflected rays meet Focal length (f): distance from the focal point to the mirror

12. Consider the situation where an object is beyond the center of curvature: Remember: any ray of light traveling parallel to the principal axis will reflect through the focal point. The image appears both smaller and inverted.

13. Now consider if the object were between C and F: The image is inverted and larger.

14. Finally consider the case where the image is within the focal point, F: The image is larger and upright.

15. Convex Mirrors
Convex mirrors reflect light from their outside surface. Because of this the reflected rays always diverge. Since there is no true focal point it is placed behind the mirror

16. Consider an object at any point in front of a convex mirror
Consider an object at any point in front of a convex mirror. The image is always smaller and upright!