Wave Mechanics Question 751
Question: If the length of a stretched string is shortened by 40% and the tension is increased by 44%, then the ratio of the final and initial fundamental frequencies is
[EAMCET 2003]
Options:
A) 2 : 1
B) 3 : 2
C) 3 : 4
D) 1 : 3
Show Answer
Answer:
Correct Answer: A
Solution:
Fundamental frequency in case of string is $ n=\frac{1}{2l}\sqrt{\frac{T}{m}}\Rightarrow n\propto \frac{\sqrt{T}}{l}\Rightarrow \frac{n’}{n}=\sqrt{\frac{T’}{T}}\times \frac{l}{l’} $ putting $ T’=T+0.44T=\frac{144}{100}T $ and $ l’=l-0.4l=\frac{3}{5}l $ We get $ \frac{n’}{n}=\frac{2}{1} $ .
BETA
