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HomeUP Board Class 12 › Magnetism & EMI › A coil of $N$ turns and area $A$ rotates with an…

A coil of $N$ turns and area $A$ rotates with angular velocity $\omega$ about an axis perpendicular to a uniform magnetic field $B$. The peak induced EMF is:

A$NBA\omega$
B$\dfrac{1}{2}NBA\omega$
C$NBA$
D$NBA\omega^2$
Answer & Solution
Correct answer: A. $NBA\omega$
The flux through the coil is $\Phi(t) = NBA\cos(\omega t)$, so $\varepsilon = -d\Phi/dt = NBA\omega \sin(\omega t)$. The amplitude is $\varepsilon_0 = NBA\omega$. This is the basic AC-generator EMF expression.
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