Question

Consider the phenomenon of beats & select the correct statement.

(a) It occurs when frequencies are close or equal

(b) It correspond to the change in intensity we hear due to interference of 2 waves having close frequencies

(c) It corresponds to a constant intensity sound heard during wave interference

(d) Beat frequency is variable

This question was posed to me during an interview.

My query is from Waves topic in section Waves of Physics – Class 11

Answer 1

The correct answer is (b) It correspond to the change in intensity we hear due to interference of 2 waves having close frequencies

Best explanation: When two waves with close, but not equal, frequencies interfere, beats are produced. They have a frequency equal to the average frequency of the two interfering waves and we recognize them as the variable intensity sound we hear.