Two vibrating tuning forks produce progressive waves given by Y1=4 sin 500πt  and  Y2=2 sin 506πt. Number of beats produced per minute is

From the given equations of progressive waves ω1=500π  and  ω2=506π   ∴ n1=250  and  n2=253  So beat frequency=n2−n1=253−250=3 beats per sec  ∴ Number of beats per min = 180.