The frequency of vibration can be varied. The two sources always vibrate in phase but have
different amplitudes of vibration.
A microphone M is situated a distance 100 cm from S1 along a line that is normal to S1S2.
As the frequency of S1 and S2 is gradually increased, the microphone M detects maxima and
minima of intensity of sound.

(b) The speed of sound in air is 330 m s–1.
The frequency of the sound from S1 and S2 is increased. Determine the number of
minima that will be detected at M as the frequency is increased from 1.0 kHz to 4.0 kHz.

Question

The frequency of vibration can be varied. The two sources always vibrate in phase but have
different amplitudes of vibration.
A microphone M is situated a distance 100 cm from S1 along a line that is normal to S1S2.
As the frequency of S1 and S2 is gradually increased, the microphone M detects maxima and
minima of intensity of sound.

(b) The speed of sound in air is 330 m s–1.
The frequency of the sound from S1 and S2 is increased. Determine the number of
minima that will be detected at M as the frequency is increased from 1.0 kHz to 4.0 kHz.