Explain the construction and working of a pinhole camera.
- Take an ordinary hollow rectangular cardboard box with a small hole in the middle of one face of the box.
- The size of the hole should be equal to the pinhead of a common pin.
- Remove the opposite face of the box and fix a wax paper in its place with the help of a thread or a rubber band.
- The box is blacken from inside so that any light which falls on its walls directly or indirectly is absorbed.
Working of a pinhole camera
- Place a luminous object such as a burning wick (XY) of the candle in front of the pinhole, an inverted picture X’Y’ of the wick is obtained on the wax paper. This picture is called the image .
- The image obtained is inverted.
- Such an image is formed because the light travels in a straight path. Hence, light from the upper point X of the wick passes through the pinhole and strikes the wax paper at X’.
Similarly, light from the lower point Y of the wick passes through the pinhole and strikes the wax paper (or screen) at Y’.
- When light from all other points between X and Y passes through the pinhole they strike the wax paper in between X’ and Y’. Hence, an inverted image is formed on the wax paper.