Question

Two interfering waves have a frequency of 2Hz & 6Hz. What is the beat frequency?

(a) 8Hz

(b) 4Hz

(c) 2Hz

(d) 0

The question was posed to me in an interview for internship.

This interesting question is from Waves topic in chapter Waves of Physics – Class 11

Answer 1

Right choice is (b) 4Hz

Easiest explanation: Beat frequency is equal to the difference between frequencies of interfering waves.                       In this case, beat frequency

= 6-2 = 4Hz.