JEE Main & Advanced Sample Paper JEE Main - Mock Test - 29

  • question_answer
    In the expression for torque \[\tau =a\times L+b\times I/\omega \],L represents angular momentum, I is moment of inertia and \[\omega \] is angular velocity. The dimensions of a x b are

    A) \[[{{M}^{0}}{{L}^{0}}{{T}^{-4}}]\]   

    B)   \[[{{M}^{0}}{{L}^{0}}{{T}^{-2}}]\]

    C) \[[{{M}^{0}}{{L}^{0}}{{T}^{-1}}]\]           

    D) \[[{{M}^{0}}{{L}^{0}}{{T}^{-3}}]\]

    Correct Answer: A

    Solution :

    [a] : Given, \[\tau =a\times L+b\times I/\omega \] \[\therefore \]\[[a]=\frac{[\tau ]}{[L]}=\frac{[I\alpha ]}{[I\omega ]}=\frac{[{{T}^{-2}}]}{[{{T}^{-1}}]}=[{{T}^{-1}}]\] \[[b]=\frac{[\tau ]}{[I/\omega ]}=\frac{[I\alpha ]}{[I/\omega ]}=[\alpha \omega ]=[{{T}^{-2}}][{{T}^{-1}}]=[{{T}^{-3}}]\] \[\therefore \]\[[a\times b]=[{{T}^{-1}}][{{T}^{-3}}]=[{{M}^{0}}{{L}^{0}}{{T}^{-4}}]\]


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