JEE Mains · Physics · STD 12 -Electromagnetic induction
- JEE Mains 2025
- Easy
- MCQ
A coil of area A and N turns is rotating with angular velocity \(\omega\) in a uniform magnetic field \(\vec{B}\) about an axis perpendicular to \(\vec{B}\). Magnetic flux \(\varphi\) and induced \(\operatorname{emf} \varepsilon\) across it, at an instant when \(\vec{B}\) is parallel to the plane of coil, are :
Pick an option to check your answer.
Answer & Solution
Correct Answer
(C) \(\varphi=0, \varepsilon=\mathrm{NAB} \omega\)
Step-by-step Solution
Detailed explanation
\(\begin{aligned}
\phi & =\mathrm{BAN} \cdot \cos (\omega \mathrm{t}) \\
\varepsilon & =\frac{-\mathrm{d} \phi}{\mathrm{dt}}=\mathrm{BA} \omega \mathrm{~N} \cdot \sin (\omega \mathrm{t})
\end{aligned}\)
When \(B\) is parallel to plane, \(\underline{\underline{\omega t}}=\frac{\pi}{2}\)
\(\Rightarrow \phi=0, \varepsilon=\mathrm{BA} \omega \mathrm{~N}\)
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