JEE Mains · Physics · STD 12 -6. Electromagnetic induction
A coil of inductance \(2\, H\) having negligible resistance is connected to a source of supply whose voltage is given by \(V=3 t\) volt. (where \(t\) is in second). If the voltage is applied when \(t =0,\) then the energy stored in the coil after \(4\, s\) is ............ \(J\).
- A \(144\)
- B \(121\)
- C \(169\)
- D \(108\)
Answer & Solution
Correct Answer
(A) \(144\)
Step-by-step Solution
Detailed explanation
\(\varepsilon=\frac{L dI }{ dt }\) \(3 \int_{0}^{4} t dt =2 \int_{0}^{ I } d I\) \(\frac{3}{2} \times 16=2 I\) \(I =12\) \(V =\frac{1}{2} LI ^{2}=\frac{1}{2} \times 2(12)^{2}=144 J\)
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