NEET Solved Paper 2014 Question 21
Question: The number of possible natural oscillations of air column in a pipe closed at one end of length 85 cm whose frequencies lie below 1250 Hz are (velocity of sound = 340 $ m{s^{-1}} $ ) [AIPMT 2014]
Options:
A) 4
B) 5
C) 7
D) 6
Show Answer
Answer:
Correct Answer: D
Solution:
For pipe closed at one end $ f _{n}=n( \frac{v}{4l} ) $ here n is an odd number.
$ =n[ \frac{340}{4\times 85\times {10^{-2}}} ] $ $ =n[100] $
Here, n is an odd number, so for the given condition n can go up to n =11
because for n =13 condition will not be valid. N = 1, 3, 5, 7, 9, 11 So, number of possible natural oscillations could be 6.
