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JEE Mains · Physics · STD 12 -6. Electromagnetic induction
In a coil of resistance \(8 \Omega\), the magnetic flux due to an external magnetic field varies with time as \(\phi=\frac{2}{3}\left(9- t ^{2}\right)\). The value of total heat produced in the coil, till the flux becomes zero, will be \(....J\)
- A \(6\)
- B \(5\)
- C \(2\)
- D \(3\)
Answer & Solution
Correct Answer
(C) \(2\)
Step-by-step Solution
Detailed explanation
\(\phi=\frac{2}{3}\left(9-t^{2}\right)=0\) \(t=3\,\sec\) \(e=\frac{-d \phi}{d t}=-\frac{2}{3}(0-2 t)=\frac{4 t}{3}\) Heat produced in \(3\,sec =\int \frac{ e ^{2}}{ r } dt =\int_{0}^{3} \frac{16 t ^{2}}{9 \times 8} dt =2\,J\)
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