JEE Main & Advanced Physics Electro Magnetic Induction Question Bank Critical Thinking

  • question_answer
    An inductor of 2 henry and a resistance of 10 ohms are connected in series with a battery of 5 volts. The initial rate of change of current is                                                 [MP PMT 2001]

    A)            0.5 amp/sec                         

    B)            2.0 amp/sec

    C)            2.5 amp/sec                         

    D)            0.25 amp/sec

    Correct Answer: C

    Solution :

                       \[i={{i}_{0}}\left( 1-{{e}^{\frac{-Rt}{L}}} \right)\Rightarrow \frac{di}{dt}=\frac{d}{dt}{{i}_{0}}-\frac{d}{dt}{{i}_{0}}{{e}^{\frac{-Rt}{L}}}\]                    \[\Rightarrow \frac{di}{dt}=0-{{i}_{0}}\left( -\frac{R}{L} \right)\ {{e}^{-\frac{Rt}{L}}}=\frac{{{i}_{0}}R}{L}{{e}^{-\frac{Rt}{L}}}\]            Initially, \[t=0\Rightarrow \frac{di}{dt}=\frac{{{i}_{0}}\times R}{L}=\frac{E}{L}=\frac{5}{2}=2.5\ amp/sec.\]


You need to login to perform this action.
You will be redirected in 3 sec spinner