Explain the formation of image of a luminous object in a pin hole camera with the aid of a neat diagram.

Working and formation of image :

If a luminous object AB, such as a lighted candle, is placed in front of the pin hole, an inverted picture A'B' of the candle is obtained on the tracing paper. This picture A'B' is called the image. The image obtained is upside down (i.e. inverted). The reason is that light travels in a straight line path. Hence, light from the upper point A of the candle passes through the pin hole and strikes the tracing paper at A'. Similarly, light from the lower point B of the candle passes through the pin hole and strikes the tracing paper (or screen) at B'. Light rays from all the other points between A and B, on passing through the pin hole strike the tracing paper in between A' and B'. As a result, an inverted image of the candle is seen on the tracing paper.

Below figure shows the simple ray diagram for the formation of image :