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Question : 3 of 27
Marks: +1, -0
A steel wire has a length of 12.0 m and a mass of 2.10 kg. What should be the tension in the wire so that speed of a transverse wave on the wire equals to the speed of sound in dry air at 20 °C = 343 ms1\mathrm{m}\,\mathrm{s}^{-1}.
Solution:  
Here, l=12.0l = 12.0 m, M = 2.10 kg, T = ?, v = 343 ms1\mathrm{m}\,\mathrm{s}^{-1}
Mass per unit length, µ
=Ml=2.1012.0=0.175kgm1= \frac{M}{l}= \frac{2.10}{12.0}=0.175\,\frac{\mathrm{kg}}{\mathrm{m}^{-1}}
As, v=Tμv=\sqrt{\frac{T}{\mu}}
T=v2.μ=(343)2×0.175\therefore T=v^{2}.\,\mu=(343)^{2}\times 0.175 =2.06×104N=2.06\times 10^{4}\,\mathrm{N}
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