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A source of unknown frequency gives 4 beats/s, when sounded with a source of known frequency 250 Hz. The second harmonic of the source of unknown frequency gives five beats per second, when sounded with a source of frequency 513 Hz. The unknown frequency is
A
260 Hz
B
254 Hz
C
246 Hz
D
240 Hz
Detailed Solution
Frequency of the unknown source = 246 Hz or 254 Hz
Its second harmonic = 492 Hz or 508 Hz
Only 508 Hz gives 5 beats per second with 513 Hz, so the unknown frequency = 254 Hz
Its second harmonic = 492 Hz or 508 Hz
Only 508 Hz gives 5 beats per second with 513 Hz, so the unknown frequency = 254 Hz
