Question 162: Electromagnetic Induction

Question

A ceiling fan having 3 blades of length $$80 \mathrm{~cm}$$ each is rotating with an angular velocity of 1200 $$\mathrm{rpm}$$. The magnetic field of earth in that region is $$0.5 \mathrm{G}$$ and angle of dip is $$30^{\circ}$$. The emf induced across the blades is $$\mathrm{N} \pi 	imes 10^{-5} \mathrm{~V}$$. The value of $$\mathrm{N}$$ is _________.

Accepted Answer

$$\begin{aligned}
& B_v=B \sin 30=\frac{1}{4} 	imes 10^{-4} \
& \omega=2 \pi 	imes f=\frac{2 \pi}{60} 	imes 1200 \mathrm{~rad} / \mathrm{s} \
& \varepsilon=\frac{1}{2} B_V \omega \ell^2 \
& =32 \pi 	imes 10^{-5} \mathrm{~V}
\end{aligned}$$

Electromagnetic Induction

Choose the correct answer: