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Question
A tuning fork produces 4 beats per second with another tuning fork of frequency 256 Hz. The first one is now loaded with a little wax and the beat frequency is found to increase to 6 per second. What was the original frequency of the tuning fork?
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Solution
Frequency of tuning fork A : \[n_1\] = 256 Hz
No. of beats/second m = 4
Frequency of second fork B : \[n_2\] =?
\[n_2 = n_1 \pm m\]
\[\Rightarrow\] \[n_2 = 256 \pm 4\]
\[\Rightarrow\] \[n_2\] = 260 Hz or 252 Hz
Now, as it is loaded with wax, its frequency will decrease.
As it produces 6 beats per second, the original frequency must be 252 Hz.
260 Hz is not possible because on decreasing the frequency, the beats per second should decrease, which is not possible.
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