JEE Main & Advanced Physics Elasticity Question Bank Youngs Modulus and Breaking Stress

  • question_answer
    A wire is stretched by 0.01 m by a certain force F. Another wire of same material whose diameter and length are double to the original wire is stretched by the same force. Then its elongation will be               [EAMCET (Engg.) 1995; CPMT 2001]

    A) 0.005 m

    B)                             0.01 m

    C)                 0.02 m

    D)                             0.002 m

    Correct Answer: A

    Solution :

        \[l=\frac{FL}{\pi {{r}^{2}}Y}\]\ \[l\propto \frac{L}{{{r}^{2}}}\] (Y and F are constant) \[\frac{{{l}_{2}}}{{{l}_{1}}}=\frac{{{L}_{2}}}{{{L}_{1}}}\times {{\left( \frac{{{r}_{1}}}{{{r}_{2}}} \right)}^{2}}=(2)\times {{\left( \frac{1}{2} \right)}^{2}}=\frac{1}{2}\] Þ \[{{l}_{2}}=\frac{{{l}_{1}}}{2}=\frac{0.01m}{2}=0.005m\]


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