Igcse Model Questions Vol1 2022 Physics Question 31

A rectangular conducting loop of width \(0.08\,\text{m}\) and length \(0.12\,\text{m}\) lies completely within a uniform magnetic field of magnitude \(0.5\,\text{T}\) that is perpendicular to the plane of the loop. The loop is pulled out of the field at a constant speed \(v\) so that the side of width \(0.08\,\text{m}\) exits first. (a) Determine the speed \(v\) required for the average induced emf during the whole extraction to be \(0.20\,\text{V}\). (b) When the loop is half‑out, calculate the magnetic force on the side of length \(0.12\,\text{m}\) that is still inside the field, given that a clockwise current of \(3\,\text{A}\) flows in the loop (viewed from above). (c) Find the mechanical power that must be supplied to keep the loop moving at this speed against the magnetic drag when it is half‑out.