JEE Main & Advanced Sample Paper JEE Main Sample Paper-43

  • question_answer
    A rectangular coil of 100 turns and size \[0.1m\times 0.05\,m\] is placed perpendicular to amagnetic field of 0.1 T. The induced \[emf\] when the field drops to 0.05 T is 0.05 s is

    A)  0.5V              

    B)  1.0V

    C)  1.5V              

    D)  2.0V

    Correct Answer: A

    Solution :

     Area of the coil \[\Rightarrow \] Change in magnetic field = 0.05 - 0.1 = -0.05T Therefore, change in flux is \[M=(AL)d\,\,\,\Rightarrow \,\,\frac{M}{Ad}\] \[\Rightarrow \] Induced emf for one turn \[T=2\pi \,\,\sqrt{\frac{M}{2Adg}}\] \[\Delta DBS,\] Induced emf for 100 turns (in magnitude)  \[SD=\sqrt{{{60}^{2}}+{{25}^{2}}}\] \[=\sqrt{4225}=65=DP\]

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