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In an experiment to determine the Young's modulus of wire of a length exactly \mathrm{1 \mathrm{~m},} the extension in the length of the wire is measured as \mathrm{0.4 \mathrm{~mm}} with an uncertainty of \mathrm{\pm 0.02 \mathrm{~mm}} when a load of \mathrm{1 \mathrm{~kg}} is applied. The diameter of the wire is measured as \mathrm{0.4 \mathrm{~mm}} with an uncertainty of  \mathrm{\pm 0.01 \mathrm{~mm}. }The error in the measurement of Young's modulus \mathrm{(\Delta \mathrm{Y})} is found to be \mathrm{x \times 10^{10} \mathrm{Nm}^{-2}.} The value of \mathrm{x} is _____________.

\mathrm{\left(\text { take } \mathrm{g}=10 \mathrm{~ms}^{-2}\right)}

Option: 1

2


Option: 2

-


Option: 3

-


Option: 4

-


Answers (1)

best_answer

\mathrm{L=1 \mathrm{~m} }

\mathrm{Extension=l=0.4mm}

                    \mathrm{=4\times 10^{-4}m}

\mathrm{\Delta L =0.02 \mathrm{~mm}}

        \mathrm{=2\times 10^{-5}m}

\mathrm{m =1 \mathrm{~kg} }

\mathrm{d =0.4 \mathrm{~mm}=4 \times 10^{-4} \mathrm{~m} }

\mathrm{\Delta d =1 \times 10^{-5} \mathrm{~m}}

\mathrm{ Y =\frac{m g}{A} \times \frac{L}{l} }

\mathrm{\frac{\Delta Y}{Y} =\frac{\Delta m}{m}+\frac{\Delta L}{L}+\frac{2 \Delta d}{d}+\frac{\Delta l}{l} }

\mathrm{=0+0+2\left(\frac{0.01}{0.4}\right)+\left(\frac{0.02}{0.4}\right) }

\mathrm{=\frac{1}{20}+\frac{1}{20}=\frac{2}{20} }

\mathrm{\Delta Y =\frac{Y}{10}= \frac{m g \times L}{(A l) 10} }

\mathrm{\Delta Y=\frac{1\times 10\times 1}{3.14\times \frac{16\times 10^{-8}}{4}\times 0.4\times 10^{-3}\times 10}}

\mathrm{\Delta Y=2\times 10^{10}}

The Value of \mathrm{x} is \mathrm{2}

 












 

Posted by

Devendra Khairwa

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