question_answer

Beats are produced by frequencies \[{{f}_{1}}\]and \[{{f}_{2}}\left( {{f}_{1}}>{{f}_{2}} \right).\]The duration of time between two successive maxima or minima is equal to

A) \[\frac{1}{{{f}_{1}}+{{f}_{2}}}\]                                 

B) \[\frac{2}{{{f}_{1}}-{{f}_{2}}}\]

C) \[\frac{2}{{{f}_{1}}+{{f}_{2}}}\]                                 

D) \[\frac{2}{{{f}_{1}}-{{f}_{2}}}\]