2. Questions Bank
  3. 12th Class
  4. Physics
  5. Alternating Current / प्रत्यावर्ती धारा

12th Class Physics Alternating Current / प्रत्यावर्ती धारा Question Bank MCQ - Alternating Currents

  • question_answer
    An LC circuit contains a 20 mH inductor and a \[50\text{ }\mu F\] capacitor with an initial charge of 10 mC. The resistance of the circuit is negligible. Let the instant at which the circuit which is closed be \[t=0\]. At what time the energy stored is completely magnetic?

    A) 1 = 0               

    B) t = 1.57 ms

    C) t = 3.14 ms                  

    D) t = 6.28 ms

    Correct Answer: B

    Solution :

    (b) t = 1.57 ms At time \[t=\frac{T}{4}\], energy stored is completely magnetic. Time, \[t=\frac{T}{4}=\frac{2\pi \sqrt{LC}}{4}\] \[\Rightarrow t=\frac{\pi \sqrt{20\times {{10}^{-3}}\times 50\times {{10}^{-6}}}}{2}\]             \[t=\frac{\pi \sqrt{1000\times {{10}^{-9}}}}{2}=\frac{\pi \sqrt{1\times {{10}^{-6}}}}{2}=1.57\,\,ms\]


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