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

  • question_answer
    The extension of a wire by the application of load is 3 mm. The extension in a wire of the same material and length but half the radius by the same load is                    [CMEET Bihar 1995]

    A) 12 mm

    B)                             0.75 mm

    C)                 15 mm   

    D)                 6 mm

    Correct Answer: A

    Solution :

        \[l=\frac{FL}{AY}\Rightarrow l\propto \frac{1}{{{r}^{2}}}\] (F,L and Y are constant)             \[\frac{{{l}_{2}}}{{{l}_{1}}}={{\left( \frac{{{r}_{1}}}{{{r}_{2}}} \right)}^{2}}={{(2)}^{2}}\Rightarrow {{l}_{2}}=4{{l}_{1}}=4\times 3=12mm\]


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