JEE Mains · Physics · STD 12 -6. Electromagnetic induction
When a coil is placed in a time dependent magnetic field the power dissipated in it is \(P\). The number of turns, area of the coil and radius of the coil wire are \(N\), \(A\) and \(r\) respectively. For a second coils number of turns, area of the coil and radius of the coil wire are \(2N\), \(2A\) and \(3r\) respectively. When the first coil is replaced with second coil the power dissipated in it is \(\sqrt{2}\,\alpha P\). The value of \(\alpha\) is _______.
- A \(36\)
- B \(128\sqrt{2}\)
- C \(16\)
- D \(64\)
Answer & Solution
Correct Answer
(A) \(36\)
Step-by-step Solution
Detailed explanation
The induced emf in the coil is given by Faraday's law: \(E = N A \dfrac{dB}{dt}\) The resistance of the coil is \(R = \rho \dfrac{l}{a}\), where \(l\) is the total length of the wire and \(a\) is its cross-sectional area. The length of the wire is \(l = N (2\pi R_c)\), where…
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