JEE Main · 2025 · 22 Jan 2025 · Shift 2 · Electromagnetic Induction

While the loop is partially inside the field and being pulled out at constant speed v, the motional emf is
$\epsilon =B\ell v$

Here B (field strength), $\ell$ (length of the side still inside the field, perpendicular to the velocity) and v are all constant during this interval, so $\epsilon$ stays constant throughout. Before the loop starts leaving, and after it has fully left, there is no change of flux and $\epsilon =0$.

So the graph of $|\epsilon |$ against time, while the loop is partially inside the field, is a constant horizontal line — a rectangular pulse of height $B\ell v$.