JEE Main & Advanced Physics Alternating Current / प्रत्यावर्ती धारा Question Bank Critical Thinking

  • question_answer
    A virtual current of 4A and 50 Hz flows in an ac circuit containing a coil. The power consumed in the coil is 240 W. If the virtual voltage across the coil is 100 V its inductance will be

    A)            \[\frac{1}{3\pi }\]H            

    B)            \[\frac{1}{5\pi }H\]

    C)            \[\frac{1}{7\pi }H\]            

    D)            \[\frac{1}{9\pi }H\]

    Correct Answer: B

    Solution :

                       \[R=\frac{P}{i_{rms}^{2}}=\frac{240}{16}=15\Omega \]                    \[Z=\frac{V}{i}=\frac{100}{4}=25\Omega \]                    Now \[{{X}_{L}}=\sqrt{{{Z}^{2}}-{{R}^{2}}}=\sqrt{{{(25)}^{2}}-{{(15)}^{2}}}=20\Omega \]            \[\therefore 2\pi \nu L=20\Rightarrow L=\frac{20}{2\pi \times 50}=\frac{1}{5\pi }Hz\]


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