Wave Motion 2 Question 34
34. Velocity of sound in air is $320 m / s$. A pipe closed at one end has a length of $1 m$. Neglecting end corrections, the air column in the pipe can resonate for sound of frequency
$(1989,2 M)$
(a) $80 Hz$
(b) $240 Hz$
(c) $320 Hz$
(d) $400 Hz$
Show Answer
Answer:
Correct Answer: 34. (a, b, d)
Solution:
- For closed pipe, $f=n\left(\frac{v}{4 l}\right) n=1,3,5 \ldots$
For $n=1, \quad f _1=\frac{v}{4 l}=\frac{320}{4 \times 1}=80 Hz$
For $n=3, \quad f _3=3 f _1=240 Hz$
For $n=5, \quad f _5=5 f _1=400 Hz$
$\therefore$ Correct options are (a), (b) and (d).
