Two waves of slightly different frequencies `f_(1) and f_(2) (f_(1) gt f_(2))` with zero phase difference , same amplitudes ,travelling in the same direction superimpose .

Options

A. Phenomenon of beats is always observed by human ear
B. Intensity of resultant wave is a constant
C. Intensity of resultant wavevariesperiodically with time withmaximumintensity4
D. A maxima appears at a time `(1)/(2(f_(1) -f_(2)))` later (or earlier) than a minima appears

Answer

C, D

Explanation

By defmitions of constructive and destructive interference ofequalamplitude waves option (C)is correct and by definition of beats option (D) is also correct.