# NEET Physics Waves Questions Solved

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An organ pipe is closed at one end has fundamental frequency of 1500 Hz. The maximum number of overtones generated by this pipe which a normal person can hear is :

(1) 14

(2) 13

(3) 6

(4) 9

(3) Critical hearing frequency for a person is 20,000Hz.

If a closed pipe vibration in Nth mode then frequency of vibration $n=\frac{\left(2N-1\right)v}{4l}=\left(2N-1\right){n}_{1}$

(where n1 = fundamental frequency of vibration)

Hence 20,000 $=\left(2N-1\right)×1500$$N=7.1\approx 7$

Also, in closed pipe

Number of over tones = (No. of mode of vibration) – 1

= 7 – 1 = 6.

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