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QNEET-2013-Ph-1505: NEET 2013 Physics - Class 11 NEET-2013-Ph-1505 Solution: A source of unknown frequency gives 4 beats/s when sounded with …
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 240 Hz 260 Hz 254 Hz 246 Hz
Multiple Choice Options
- A 240 Hz
- B 260 Hz
- C 254 Hz
- D 246 Hz
Step-by-Step Verified Solution
Let _ be frequency of the unknown source. As it gives 4 beats per second when sounded with a source of frequency 250 Hz,
_ _ = 250 � 4 = 246 H z o r 254 H z
Second harmonic of this unknown source = 492 Hz or 508 Hz which gives 5 beats per second, when sounded with a source of frequency 513 Hz.
Therefore unknown frequency, _ = 254 Hz.