Question

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

Answer 1

Answer: (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

Answer 2

If two waves of nearly equal frequency superpose, they give beats if they both travel in straight line and $I_{\min}$if they have equal amplitudes.