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The speed of a transverse wave passing through a string of length 50 \mathrm{~cm} and mass 10 \mathrm{~g} is 60 \mathrm{~ms}^{-1}. The area of cross-section of the wire is 2.0 \mathrm{~mm}^{2} and its Young's modulus is 1.2 \times 10^{11} \mathrm{Nm}^{-2}. The extension of the wire over its natural length due to its tension will be \mathrm{x \times 10^{-5} \mathrm{~m}}. The value of \mathrm{x } is___________.

Option: 1

15


Option: 2

-


Option: 3

-


Option: 4

-


Answers (1)

best_answer

\mathrm{\ell=0.5 \mathrm{~m} }

\mathrm{m=10 g=10^{-2} \mathrm{~kg} }

\mathrm{V=60 \frac{\mathrm{m}}{\mathrm{s}}=\sqrt{\frac{\mathrm{T}}{\mathrm{\mu }}} }

\mathrm{A=2 \times 10^{-6} \mathrm{~m}^2 }

\mathrm{Y=1.2 \times 10^{11} \mathrm{~N} / \mathrm{m}^2 }

\mathrm{\Delta \ell=x \times 10^{-5} \mathrm{~m} }

\mathrm{\mu V^2=T }

\mathrm{\left(\frac{10^{-2}}{0.5}\right)(60)^2 =T }

\mathrm{\frac{36}{0.5} =T }

\mathrm{T=72 \mathrm{H} }

\mathrm{Y=\frac{F}{A} \times \frac{\ell}{\Delta \ell} }

\mathrm{1.2 \times 10^{11} =\frac{72}{2 \times 10^{-6}} \times \frac{0.5}{x \times 10^{-5}} }

\mathrm{x =\frac{18}{1.2} }

\mathrm{x =15}














 

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