Question

In the given arrangement, the loop is moved with constant velocity $V$ in a uniform magnetic field $B$ in a restricted region of width $a$. The time for which the $\text{emf}$ is induced in the circuit is

• A. $\frac{2b}{V}$
• B. $\frac{2a}{V}$
• C. $\frac{(a+b)}{V}$
• D. $\frac{2(a-b)}{V}$

Answer 1

The correct option is B $\frac{2a}{V}$


Flux in the loop will change only when either $AD$ or $BC$ is in the magnetic field.
$BC$ is inside magnetic region for time interval of $\frac{a}{V}$ and $AD$ is inside magnetic region for time interval of $\frac{a}{V}$.

$\text{emf}$ is observed in the loop for interval of
$\Rightarrow T=\frac{2a}{V}$
Ans: $B$