Wave Motion 2 Question 35
35. 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 (Speed of sound in air $=330 m / s$ )
$(1985,2 M)$
(a) 31.25
(b) 62.50
(c) 93.75
(d) 125
Show Answer
Answer:
Correct Answer: 35. (a, c)
Solution:
- For closed organ pipe,
$ \begin{array}{ll} & f=n\left(\frac{v}{4 l}\right) \text { where, } n=1,3,5 \ldots \ldots \\ \therefore & l=\frac{n v}{4 f} \\ \text { For } n=1, & l _1=\frac{(1)(330)}{4 \times 264} \times 100 cm=31.25 cm \\ \text { For } n=3, & l _3=3 l _1=93.75 cm \\ \text { For } n=5, & l _5=5 l _1=156.25 cm \\ \therefore \quad \text { Correct options are (a) and (c). } \end{array} $
