Pin-hole Camera :
Pin hole camera is based on rectilinear propagation of light principle that mean light travel in straight path. In pin hole camera, lens or any transparent material is not required. Let’s see how pin hole camera is made.
Activity
Take two different size cylinder. Take first cylinder in your hand make small hole in one end and another end is open. Now take another cylinder create small rectangular shape hole at one end and make pin hole in another end. Small piece of trace paper is place at rectangular hole.
Now fixed both cylinder with each other in such a way that second cylinder fixes at open end of first cylinder. Now see the object in light by pin hole. What will be your observation? Image of a tree is formed inverted in camera. But we place camera in normal way, why the image of camera is formed as inverted? Because light ray from top of tree M is fall on tracing paper at M’ after passing through pin hole. And light ray
from bottom of tree N is falling on a tracing paper at N’ after passing through pin hole. Therefore image of tree formed as inverted in camera.
Q. 1 What happen when light ray does not travel in straight path?
Ans : If light ray not travel in straight path then image not formed in pin hole camera.
Q. 2 If a circular hole of the same size is made instead of rectangular hole, will the image be formed?
Ans : Yes. There will be an image be formed.