Question

If we place a sewing needle in front of an electric bulb we do not see its shadow on the wall

Answer 1

Light may be considered to be a wave. When a very small object like the needle is kept in front of the bulb, the light waves tend to bend around it and not travel in a straight path. Hence the shadow of the small object is not seen

Answer 2

Answer:

• If we place a sewing needle in front of an electric bulb, we do not see its shadow on the wall. This is because of the small width of the needle.
• As we know, when light waves encounter any obstacle, they bend around the edges of the obstacle.
• If the dimensions of the obstacle are comparable to the wavelength of the waves.
• This bending of light around the edges of an obstacle is called diffraction of light.

• Due to the small width of the needle, light from the electric bulb diffracts around both sides which causes no shadow of the needle.

Hence if we place a sewing needle in front of an electric bulb we do not see its shadow on the wall.

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