A square shaped coil of area $70 \mathrm{~cm}^{2}$ having 600 turns rotates in a magnetic field of $0.4 ~\mathrm{wbm}^{-2}$, about an axis which is parallel to one of the side of the coil and perpendicular to the direction of field. If the coil completes 500 revolution in a minute, the instantaneous emf when the plane of the coil is inclined at $60^{\circ}$ with the field, will be ____________ V. (Take $\pi=\frac{22}{7}$)
Answer (integer)
44
Solution
Area $(\mathrm{A})=70 \mathrm{~cm}^2=70 \times 10^{-4} \mathrm{~m}^2$
<br/><br/>$\mathrm{B}=0.4 \mathrm{~T}$
<br/><br/>$f=\frac{500 \text { revolution }}{60 \text { minute }}=\frac{500}{60} \frac{\text { rev. }}{\mathrm{sec} .}$
<br/><br/>Induced emf in rotating coil is given by
<br/><br/>$$
\begin{aligned}
& e=N \omega B A \sin \theta \\\\
& =600 \times 2 \times \frac{22}{7} \times \frac{500}{60} \times 0.4 \times 70 \times 10^{-4} \sin 30^{\circ} \\\\
& =600 \times 2 \times \frac{22}{7} \times \frac{500}{6} \times 0.4 \times 70 \times 10^{-4} \times \frac{1}{2} \\\\
& =44 \text { Volt }
\end{aligned}
$$
About this question
Subject: Physics · Chapter: Alternating Current · Topic: AC Circuits: R, L, C
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