Observe the picture given in Fig. carefully.
A patch of light is obtained at B, when the torch is lighted as shown. Which of the following is kept at position A to get this patch of light?
(a) A wooden board
(b) A glass sheet
(c) A mirror
(d) A sheet of white paper
Option (c) is the correct answer.
A patch of light will be formed at the screen when the light from the torch gets reflected from point A and reaches the screen. A mirror is an object that reflects light falling on it. So inorder to get a patch of light, a mirror should be placed at position A.