A coil of resistance $400 \Omega$ is placed in a magnetic field. If the magnetic flux $\phi(\mathrm{Wb})$ linked with the coil varies with time $t$ (sec) as $\phi=50 t^2+4$ The current in the coil at $t=2 \mathrm{~s}$ is

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Aicharya · Accepted Answer

Induced emf of coil $E=\left|-\frac{d \phi}{d t}\right|_t$ Given, $\phi=50 t^2+4$ and $R=400 \Omega$
$\begin{aligned}
E & =\left|-\frac{d \phi}{d t}\right|_{t=2} \\
& =|100 t|_{t=2}=200 \mathrm{~V}
\end{aligned}$
Current in the coil
$\begin{aligned}
i & =\frac{E}{R}=\frac{200}{400} \\
& =\frac{1}{2}=0.5 \mathrm{~A}
\end{aligned}$

A coil of resistance $400 \Omega$ is placed in a magnetic field. If the magnetic flux $\phi(\mathrm{Wb})$…

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