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]

• A. 100 Hz
• B. 200 Hz
• C. 256 Hz
• D. 400 Hz

Answer 1

The correct option is B

200 Hz

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

$\Rightarrow 25=\frac{100}{2p}\Rightarrow p=2$ . Hence frequency of vibration

n = $\frac{p}{2l}\sqrt{\frac{T}{m}}=\frac{2}{2\times 1}\sqrt{\frac{20}{5\times {10}^{-4}}}=200Hz$