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Two tunning forks P and Q when set vibration, gives 4 beats s-1 . If a prong of the fork P is filled, the beats are reduced to 2 beats s-1 . What is frequency of P, if that of Q is 250 Hz? (a) 250 Hz (b) 246 Hz (c) 252 Hz (d) 254 Hz |
Answer» Correct option (b) 246 Hz Explanation: Possible frequencies of P are: (250 ± 4) Hz i.e. 246 Hz, 254 Hz When the prong of P is filled, its frequeney becomes greater than the original frequeney of P. Also the frequency of P when the prong is filled reduces to 2 beats s-1 . New possible frequencies of P are: (250 ± 2) Hz i.e. 248 Hz, 252 Hz Since the new frequency increases from the original frequency. So, the new frequency will be 246 Hz. |
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