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AP EAMCET · PHYSICS · Electromagnetic Induction

In an ac generator, if coil of \(\mathrm{N}\) turns and area \(\mathrm{A}\) is rotated at \(u\) revolutions per second in a uniform magnetic field \(B\), then the motional emf produced is equal to (At \(\mathrm{t}=0 \mathrm{~s}\), the coil is perpendicular to the field)

  1. A \(\operatorname{NBA}(2 \pi u) \sin (2 \pi u t)\)
  2. B \(\operatorname{NBA}^2(2 \pi v) \sin (2 \pi v t)\)
  3. C \(\mathrm{N}^2 \mathrm{~B}^2 \mathrm{~A}^2(2 \pi v) \sin (2 \pi v t)\)
  4. D \(\mathrm{NBA}(4 \pi v) \sin (2 \pi v t)\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\operatorname{NBA}(2 \pi u) \sin (2 \pi u t)\)

Step-by-step Solution

Detailed explanation

Flux, \(\phi=\mathrm{B}(\mathrm{NA}) \cos \omega \mathrm{t}\) and \(\omega=2 \pi \mathrm{v}\) \(\mathrm{emf}, \mathrm{e}=-\frac{\mathrm{d} \phi}{\mathrm{dt}}=\frac{-\mathrm{d}}{\mathrm{dt}} \mathrm{BNA} \cos \omega \mathrm{t}=-\mathrm{NBA} \omega \sin (\omega \mathrm{t})\)…