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 $\phi$ and induced emf $\epsilon$ across it, at an instant when $\vec{B}$ is parallel to the plane of coil, are :

[JEE Main 2025, 29 Jan (Shift 1)]

Question

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 $\phi$ and induced emf $\epsilon$ across it, at an instant when $\vec{B}$ is parallel to the plane of coil, are :

[JEE Main 2025, 29 Jan (Shift 1)]

YESPYQ · Accepted Answer

Correct answer: c) $\phi =0,\epsilon =NAB\omega$. $ϕ=BAN\cdot \cos (\omega t)$ $\epsilon =\frac{-dϕ}{dt}=BA\omega N\cdot \sin (\omega t)$ When B is parallel to plane, $\omega t=\frac{\pi }{2}$ $\Rightarrow ϕ=0,\epsilon =BA\omega N$

A coil of area A and N turns is rotating with angular velocity \(\omega\) in a uniform magnetic field \(\vec{B}\) about …

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