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12th Class Physics Electro Magnetic Induction Question Bank Case Based (MCQs) - Electromagnetic Induction

  • question_answer
     The induced e.m.f. in a coil of 10 henry inductance in which current varies from 9 A to 4 A in 0.2 second is:

    A) 200 V               

    B) 250 V

    C) 300 V               

    D) 350 V   

    Correct Answer: B

    Solution :

    (b) 250 V Here \[L=10\] henry, \[{{l}_{1}}=9A,{{l}_{2}}=4A\] and \[\Delta t=0.2\] second Then induced e.m.f.             \[{{\varepsilon }_{1}}=-L\frac{dl}{dt}=-L\frac{({{l}_{2}}-{{l}_{1}})}{\Delta t}\]             \[=\frac{-10\times (4-9)}{0.2}=\frac{50}{0.2}=250V\]


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