(i) Suppose a person whistles standing on the Moon. Will the person standing nearby hear the sound? Explain giving reason.
(ii) What kind of wave needs a material medium to propagate?
(i) If a person whistles on Moon, nearby person cannot hear the sound because Moon does not have atmosphere. And we know that, sound waves require material medium for their propagation.
(ii) A mechanical wave needs a material medium for its propagation, e.g. sound wave.