EAMCET Medical EAMCET Medical Solved Paper-2010

  • question_answer
    A 4.0 m long copper wire of cross-sectional area \[1.2\text{ }c{{m}^{2}}\]is stretched by a force of \[4.8\times {{10}^{3}}N,\] If Youngs modulus for copper is Y = 1.2 x 1011 N/m2, the increase in length of wire and strain energy stored per unit volume are

    A)                  \[1.32\times {{10}^{-4}}m,66\times {{10}^{3}}J\]

    B)                 \[~132\times {{10}^{-4}}m,6.6\times {{10}^{2}}J\]

    C)                  \[13.2\times {{10}^{-4}}6.6\times {{10}^{3}}J\]

    D)                  \[0.132\times {{10}^{-4}}m,66\times {{10}^{4}}J\]

    Correct Answer: C

    Solution :

                     Given, \[A=1.2\,c{{m}^{2}}\]                 \[=1.2\times {{10}^{-4}}{{m}^{2}},\]                 \[F=4.8\times {{10}^{3}}N,\]                 \[Y=1.2\times {{10}^{11}}N/{{m}^{2}}.\]                 length   \[l=\frac{F\times L}{AY}\]                 \[=\frac{4.8\times {{10}^{3}}\times 4}{1.2\times {{10}^{-4}}\times 1.2\times {{10}^{11}}}\]                 \[=13.3\times {{10}^{-4}}m\]                 The energy stored per unit volume                 \[E=\frac{1}{2}\times \frac{F}{A}\times \frac{l}{L}\]                 \[=\frac{1}{2}\times \frac{4.8\times {{10}^{3}}}{1.2\times {{10}^{-4}}}\times \frac{13.3\times {{10}^{-4}}}{4}\]                 \[E=6.6\times {{10}^{3}}\,J\]


You need to login to perform this action.
You will be redirected in 3 sec spinner