A) \[396\,\,Hz\]
B) \[400\,\,Hz\]
C) \[404\,\,Hz\]
D) \[384\,\,Hz\]
Correct Answer: A
Solution :
According to law of length of a stretched string \[n\propto \frac{1}{l}\] or \[{{n}_{1}}{{l}_{1}}={{n}_{2}}{{l}_{2}}\] Given, \[{{n}_{1}}=n-4,\,\,{{n}_{2}}=n+4,\,\,{{l}_{1}}=50\,\,cm\] \[{{l}_{2}}=49\,\,cm\] Hence, \[(n-4)\times 50=(n+4)\times 49\] or \[50n-200=49n+196\] or \[n=396\,\,Hz\]You need to login to perform this action.
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