Q 12-06-039JEE MainJEE Main 2025 (22 Jan, Shift 2)Easy
A rectangular metallic loop is moving out of a uniform magnetic field region to a field free region with a constant speed. When the loop is partially inside the magnetic field, the plot of magnitude of induced emf $(\varepsilon)$ with time $(t)$ is given by
Answer: (D) see figure
While the loop is partly inside, only the side still in the field (length $l$) cuts the field lines, and the flux changes at a steady rate:
$$\varepsilon = \left|\frac{d\phi}{dt}\right| = Blv$$
$B$, $l$ and $v$ are all constant, so $\varepsilon$ is constant in time: a horizontal line, option (4).
Solution by Sreeraj P, M.Sc Physics