Question 29 of 153

A conducting bar of length $L$ is free to slide on two parallel conducting rails as shown in the figure

Two resistors ${R}_{1}$ and ${R}_{2}$ are connected across the ends of the rails. There is a uniform magnetic field $\vec{B}$ pointing into the page. An external agent pulls the bar to the left at a constant speed $v$.
The correct statement about the directions of induced currents ${I}_{1}$ and ${I}_{2}$ flowing through ${R}_{1}$ and ${R}_{2}$ respectively is :

ABoth ${I}_{1}$ and ${I}_{2}$ are in anticlockwise directionBBoth ${I}_{1}$ and ${I}_{2}$ are in clockwise directionC${I}_{1}$ is in clockwise direction and ${I}_{2}$ is in anticlockwise directionD${I}_{1}$ is in anticlockwise direction and ${I}_{2}$ is in clockwise direction

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Answer: (C) ${I}_{1}$ is in clockwise direction and ${I}_{2}$ is in anticlockwise direction

Given, the external agent pulls the bar towards left. According to Lenz's law and Fleming's right hand rule, there will be a motional EMF generated in the bar. The right-hand rule tells us that the magnetic force on positive charges will be in downward direction and the electric equivalent circuit can be drawn as shown below.

So, ${I}_{1}$ is in the clockwise direction and ${I}_{2}$ is in the anticlockwise direction.