Q. The minimum intensity of sound is zero at a point due to two sources of nearly equal frequencies, when
A) Two sources are vibrating in opposite phase
B) The amplitude of two sources are equal
C) At the point of observation, the amplitudes of two S.H.M. produced by two sources are equal and both the S.H.M. are along the same straight line
D) Both the sources are in the same phase
Explanation
(c) If two of nearly equal frequency superpose, they give beats if they both travel in straight line and $I_{\min} = 0$ if they have equal amplitudes
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.