Concept:Beats occur when two sound waves of slightly different frequencies superpose.
The beat frequency is the absolute difference of their frequencies.
The maximum intensity depends on the sum of amplitudes, since intensity is proportional to the square of amplitude.
Explanation:Compare each wave with the standard form
x=Asin(2πft).
For
x1=2sin(1000πt), the angular frequency is
1000π.
So,
f1=2π1000π=500 Hz.
For
x2=3sin(1006πt), the angular frequency is
1006π.
So,
f2=2π1006π=503 Hz.
Beat frequency:
fbeat=∣f2−f1∣=∣503−500∣=3 Hz.
Maximum amplitude during constructive interference is the sum of individual amplitudes.
So,
Amax=2+3=5.
Maximum intensity is proportional to the square of amplitude:
Imax=(2+3)2=52=25 units.
Thus, the waves produce 3 beats per second with maximum intensity 25 units.
Answer:Option C: 3 beats/s with maximum intensity 25 units.