A student had a ball, a screen and a torch in working condition. He tried to form a shadow of the ball on the screen by placing them at different positions. Sometimes the shadow was not obtained. Explain.
An accurate shadow of any object can be formed only when the object, source of light, and the screen must be in a single straight line. So, for obtaining the shadow of the ball, the ball, torch, and the screen must be in a single line. If the shadow is not obtained then there must be some of the reasons as below:
$(i)$. Maybe the screen is far away from the ball.
$(ii)$. The beam of the light from the torch may be falling parallel to the screen on the ball.
$(iii)$. Maybe the torch is far away from the ball.
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