Q17 of 56 Page 1

What is meant by scattering of light? Use this phenomenon to explain way the clear sky appears blue or the sun appears reddish at sunrise.

Scattering of light is defined as the phenomenon of throwing light rays in random directions when it falls on a suspended particle.


The color of the clear sky during day-time is due to the phenomenon of scattering of light by the molecules of air and other particles in the atmosphere and since they have a size smaller than the wavelength of the visible light, so the particles scatters blue color light rays effectively than that of longer wavelength color.


At Sunrise or Sunset, the reddish appearance of Sun is due to scattering of light and since Red color has highest wavelength and is scattered least.


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If the image formed by a mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it? Draw a ray diagram to justify your answer. Where and why do we generally use this type of mirror?

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Both soap and detergent are some type of salts. What is the difference between them?

Describe in brief the cleansing action of soap. Why do soaps not form lather in hard water? List two problems that arise due to the use of detergents instead. of soaps.