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AP EAMCET · PHYSICS · Electromagnetic Induction

A circular coil of area \(0.01 \mathrm{~m}^2\) and 40 turns is rotated about its vertical diameter with an angular speed of 50 \(\mathrm{rad} \mathrm{s}^{-1}\) in a uniform horizontal magnetic field \(0.05 \mathrm{~T}\). If the average power loss due to joule heating is \(25 \mathrm{~mW}\), then the closed loop resistance of the coil is

  1. A \(50 \Omega\)
  2. B \(12.5 \Omega\)
  3. C \(75 \Omega\)
  4. D \(20 \Omega\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(20 \Omega\)

Step-by-step Solution

Detailed explanation

We have \(\begin{aligned} & \mathrm{e}=\frac{\mathrm{d}}{\mathrm{dt}}=\mathrm{NBA} \frac{\mathrm{d}}{\mathrm{dt}}(\sin \omega \mathrm{t}) \\ & =\mathrm{NBA} \omega \sin \omega \mathrm{t}\end{aligned}\)…