The magnetic flux through a coil of resistance $R$ changes by an amount $\Delta \phi$ in time $\Delta t$.…

The magnetic flux through a coil of resistance $R$ changes by an amount $\Delta \phi$ in time $\Delta t$. The total quantity of induced electric charge $Q$ is
  1. $\frac{\Delta \phi}{\Delta t}$
  2. $-\frac{\Delta \phi}{\Delta t}+R$
  3. $\frac{\Delta \phi}{R}$
  4. $\frac{\Delta \phi}{\Delta t} \times R$

Solution

From Faraday's law of EMI, emf induced in the circuit is given by, $e=-\frac{\Delta \phi}{\Delta t}$ And if $R$ is the resistance in the circuit then it becomes, $\begin{aligned} & I=\frac{e}{R} \\ & \quad \Rightarrow I=-\frac{\Delta \phi}{\Delta t \cdot R}\end{aligned}$ So, the total amount of charge passing through the circuit will become, $\begin{aligned} & \because \Delta Q=I \times \Delta t \\ & \Rightarrow \Delta Q=-\frac{\Delta \phi}{\Delta t \cdot R} \cdot \Delta t \\ & \Rightarrow \Delta Q=-\frac{\Delta \phi}{R}\end{aligned}$ So, the total amount of charge passing through the circuit is given by $\frac{\Delta \phi}{R}$ .

Asked in: MHT CET 2022 (10 Aug Shift 2)

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