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JEE Main & Advanced Sample Paper JEE Main - Mock Test - 40

  • question_answer
    A copper disc of radius 0.1 m is rotated about its centre with 20 revolution per second in a uniform magnetic field of 0.1 T with its plane perpendicular to the field. The emf induced across the radius of the disc is -

    A) \[\frac{\pi }{20}\] volt           

    B)        \[\frac{\pi }{10}\] volt

    C) \[20\pi \] millivolt     

    D)        \[100\pi \] millivolt

    Correct Answer: C

    Solution :

    [c] \[\varepsilon =\frac{\Beta \omega {{R}^{2}}}{2}=\frac{0.1\times (2\pi \times 20){{(0.1)}^{2}}}{2}\] \[=20\text{ }\pi \times {{10}^{-3}}volt\]


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