Wave Mechanics Question 726

Question: A stretched string of 1m length and mass $ 5\times {{10}^{-4}}kg $ is having tension of 20N. If it is plucked at 25cm from one end then it will vibrate with frequency

[RPET 1999; RPMT 2002]

Options:

A) 100 Hz

B) 200 Hz

C) 256 Hz

D) 400 Hz

Show Answer

Answer:

Correct Answer: B

Solution:

As we know plucking distance from one end $ =\frac{l}{2p} $

Therefore $ 25=\frac{100}{2p} $

Therefore $ p=2 $ . Hence frequency of vibration $ n=\frac{p}{2l}\sqrt{\frac{T}{m}}=\frac{2}{2\times 1}\sqrt{\frac{20}{5\times {{10}^{-4}}}} $ = $ 200Hz. $