Question

An excerpt from a book by Einstein and Infeld gives the following remarks concerning wave phenomena:
"A bit of gossip starting in Washington reaches New York [by word of mouth] very quickly, even though not a single individual who takes part in spreading it travels between these two cities. There are two quite different motions involved, that of the rumor, Washington to New York, and that of the persons who spread the rumor."
Identify a correct inference from the above text.

• A. The particles of the medium perform motion from one place to another.
• B. The particles of the medium perform random motion to constitute wave motion.
• C. The particles constituting the medium perform only small vibrations, but the whole motion is that of a progressive wave.
• D. None of these.

Answer 1

The correct option is C The particles constituting the medium perform only small vibrations, but the whole motion is that of a progressive wave.

Sound waves are longitudinal waves, the particle itself do not travel from one place to other, they only vibrates in their positions and only energy is being transferred from one particle to other.

Hence option (C) is correct.