Question

A bulb is kept burning just right above the following solids. Name the shape of the shadows obtained in each case. Attempt to give a rough sketch of the shadows
Ball shaped
A cylindrical pipe shaped
A book shaped

Answer 1

Hint: The bulb is kept burning just right above the solids. The light can’t pass through the solid. So the light passes and makes the shadow. Hence we are going to sketch the shadows of the given solids one by one.

Complete step-by-step answer:
A. Ball
     

Since the ball is an example of a three dimensional shape sphere its shadow is just the compression of the sphere to its two dimensional shape circle. Hence the shadow of the ball made by the light is a circle.
B. A cylindrical shaped pipe
     

Since the cylindrical pipe is an example of a three dimensional shape cylinder its shadow is just the compression of the cylinder to its two dimensional shape rectangle. Hence the shadow of the circular pipe made by the light is a rectangle.
C. Book
     

Since the book is an example of a three dimensional shape cuboid its shadow is just the compression of the cuboid to its two dimensional shape rectangle. Hence the shadow of the book made by the light is a rectangle.

Note: The straight lines which are passing by the sides of the object are responsible to make the shadow.
Here while we speak about the compression of a cylinder it can be compressed that is projected as two shapes one is rectangle and other is circle. While the pipe is held vertically we get a circle whereas we get a rectangle while it is held horizontally.