wave_mechanics critical_thinking Question 49

Question: In Melde’s experiment, the string vibrates in 4 loops when a 50 gram weight is placed in the pan of weight 15 gram. To make the string to vibrates in 6 loops the weight that has to be removed from the pan is

[MH CET 2004]

Options:

A) 0.0007 kg wt

B) 0.0021 kg wt

C) 0.036 kg wt

D) 0.0029 kg wt

Show Answer

Answer:

Correct Answer: C

Solution:

Frequency of vibration of string is given by $ n=\frac{p}{2l}\sqrt{\frac{T}{m}} $

Therefore $ p\sqrt{T}= $ constant

Therefore $ \frac{p _{1}}{p _{2}}=\sqrt{\frac{T _{2}}{T _{1}}} $ Hence$ \frac{4}{6}=\sqrt{\frac{T _{2}}{(50+15)gm\text{-}force}} $

Therefore $ T _{2}=28.8gm\text{-}f $ Hence weight removed from the pan $ =T _{1}-T _{2}=65-28.8=3.62 $ gm-force = 0.036 kg-f.