J & K CET Medical
J & K - CET Medical Solved Paper-2005
question_answer
In 1 m long open pipe what is the harmonic of resonance obtained with a tuning fork of frequency 480 Hz?
A) First
B) Second
C) Third
D) Fourth
Correct Answer:
C
Solution :
For an open pipe of length\[l,\]the frequency n is given by \[n=n.\frac{v}{2l}\] where v is velocity of sound,\[n\] the overtone. Given, \[n=480\text{ }Hz,\text{ }l=1\text{ }m;\] \[v=330\text{ }m/s\] \[n=\frac{n(2l)}{v}\] \[=\frac{480\times 2\times 1}{330}=2.9\approx 3\] Hence, this is the second overtone or third harmonic.