Question

An air column in a pipe, which is closed at one end, will be in resonance with a vibrating tuning fork of frequency $264\, Hz$ if the length of the column in cm is (velocity of sound = $330\, m/s$)

• A. 125
• B. 93.75
• C. 62.5
• D. 187.5

Answer 1

Answer: (B)

93.75

Answer 2

Given : Frequency of tuning fork, n = 264 Hz Length of column L = ? For closed organ pipe $n = \frac{v}{4l}$ $\Rightarrow l = \frac{v}{4n} = \frac{330}{4\times264} = 0.3125$ or, $l= 0.3125 \times 100 = 31.25 \,cm$ In case of closed organ pipe only odd harmonics are possible. Therefore value of $I$ will be $\left(2n - 1\right) l$ Hence option $\left(b\right) i.e. \,3 \times 31.25 = 93.75\, cm$ is correct.