Beats

Two sound waves with wavelengths and , respectively, propagate in gas with a velocity of . How many beats per second can we expect?
1.
2.
3.
4.

Each of the two strings of lengths and is tensioned separately by of force. The mass per unit length of both strings is the same and equals When both the strings vibrate simultaneously, the number of beats is:

1.		2.
3.		4.

A tuning fork of frequency makes with the vibrating string of a piano. The beat frequency decreases to when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was:
1.
2.
3.
4.

Two sources of sound placed close to each other, are emitting progressive waves given by,
and .
${}_{}$An observer located near these two sources of sound will hear:

1.	beats per second with intensity ratio between waxing and waning
2.	beats per second with intensity ratio between waxing and waning
3.	beats per second with intensity ratio between waxing and waning
4.	beats per second with intensity ratio between waxing and waning

A source of unknown frequency gives beats/s when sounded with a source of known frequency of The second harmonic of the source of unknown frequency gives five beats per second when sounded with a source of frequency of The unknown frequency will be:

1.		2.
3.		4.

Three sound waves of equal amplitudes have frequencies of and They superimpose to give beats. The number of beats produced per second will be:

1.		2.
3.		4.