Answers

2015-06-13T08:58:04+05:30
Light and sound do not have mass. Light is electromagnetic wave transverse in nature while sound is longitudinal wave but since it requires a material medium to travel it is a mechanical wave. 
Moreover matter is the one which occupies the space. But waves do not occupy space. Electromagnetic waves don't need material medium, but sound waves do need a material medium to travel. Hence light and sound aren't considered as matter.
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2015-06-13T09:23:02+05:30
Matter is one which occupies space.But light is a beam and sound is a wave, these won't occupy space .Which means they donot have any mass 
 So light and sound are not considered as matter.
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