Waves Ques 45
45. A string of $7 m$ length has a mass of $0.035 kg$. If tension in the string is $60.5 N$, then speed of a wave on the string is
[2001, 1989]
(a) $77 m / s$
(b) $102 m / s$
(c) $110 m / s$
(d) $165 m / s$
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Answer:
Correct Answer: 45.(c)
Solution:
- (c) Given : Length $(l)=7 m$
Mass $(M)=0.035 kg$ and tension $(T)=60.5 N$.
Therefore, mass of string per unit length $(m)=$ $\frac{0.035}{7}=0.005 kg / m$
speed of wave, $=\sqrt{\frac{T}{m}}$
$\Rightarrow \sqrt{\frac{60.5}{0.005}}=110 m / s$
BETA
