13. Ravi's teacher asked their class to make a pinhole camera by themselves. Ravi read the activity 5 given in his textbook on how to make a pinhole camera. But he was unable to get the image of a well lit object. He was very upset. His elder brother on observing his pinhole camera found that the hole made by him was quite large. He rectified Ravi's mistake and helped him making another pinhole camera. Now, Ravi can see the image of the object. (a) On which principle of light does a pinhole camera works? (b) Why was Ravi unable to get the image of a well lit object? (c) How does the formation of the image by a pinhole camera is affected by size of the hole? (d) What values of Ravi is shown here? ​