Plane Mirrors

When you look into a plane mirror on the wall of a room you see an image of the room behind the mirror. It is as if there were another room. Restaurants sometimes have a large mirror on one wall just to make larger after the next experience.

The position of the image formed by a mirror depends on the position of the object.

Practical work:

Support a piece of shin glass on the bench, as in Figure 3.1, it must be fat 90 to the bench. Place a small paper arrow. O. about 10 cm from of 0 will be seen in the darker the bench top the brighter the image.

Lay another identical arrow. 1. on the bench behind the glass. Move it until it coincides with the image of 0. how do the sizes of 0 and its image compare? Imagine a line joining them. What can you say about it? Measure the distances of the points of 0 and I from the glass along the line joining them. How do they compare? Try 0 at other distances.

Real and virtual image

A real image is one which can be produced on a screen as in a pinhole camera and is formed by rays that actually pass through it.

A virtual image cannot be formed on a screen and is produced by rays which it. The image in a plane mirror is virtual. Rays from a point on an object are reflected at the mirror and appear to come from the point behind the mirror where the eye imagines the rays imtenect. When produced backwards. Figure 3.2  IA and IB are construction lines and are shown by broken lines.