MHTCET 5 May 2025 Shift 2 Paper

Concept:The induced EMF is found using Faraday's law, and the induced current is obtained by applying Ohm's law with the total series resistance of the circuit.Explanation:For a single turn, the change in magnetic flux is $\Delta \phi = \phi_{2} - \phi_{1}$.For $N$ turns, the total change in flux linkage is $\Delta \Phi = N(\phi_{2} - \phi_{1})$.According to Faraday's law, the induced EMF is $E = \frac{\Delta \Phi}{t} = \frac{N(\phi_{2} - \phi_{1})}{t}$.The coil has a resistance $R$, and the galvanometer has a resistance $6R$.These are connected in series, so the total resistance of the circuit is $R_{\text{eq}} = R + 6R = 7R$.Using Ohm's law, $I = \frac{E}{R_{\text{eq}}}$.Substituting the expressions gives $I = \frac{\frac{N(\phi_{2} - \phi_{1})}{t}}{7R} = \frac{N(\phi_{2} - \phi_{1})}{7Rt}$.Answer:Option B: $\frac{N(\phi_{2} - \phi_{1})}{7Rt}$