Unit 3 Properties of waves
A plane mirror forms an image of an object, which has these properties:
- upright but laterally inverted i.e. the image is reversed left to right
- the same size as the object
- the same distance behind the mirror as the object is in front.
- Plane mirrors are used in periscopes, security mirrors and dressing table mirrors.
- Finding the position of the image using a plane mirror
- Draw any two incident rays from the object to the mirror.
- Draw in the reflected rays from these incident rays, making sure
angle of incidence = angle of reflection.
- Continue these reflected rays back straight behind the mirror using a dotted line to the point where they appear to come from.
- The image is formed where the rays appear to come from behind the mirror. This is a virtual image. A virtual image cannot be formed on a screen. If you placed a screen at position 4 in the diagram below nothing would show.
- An object is placed in front of a mirror. Construct a ray diagram showing where the position of the image will appear.
- Describe two properties of the image.