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

Draw a ray diagram to show the formation of shadow of an opaque object by a point source of light. How is the size of shadow affected if the screen is moved away from the object?

Draw a ray diagram to show the formation of umbra and penumbra both. Label the parts umbra and penumbra in your diagram.

State the conditions when only the penumbra of an opaque object is obtained on the screen.