Igcse Model Questions Vol1 2022 Physics Question 23

A rectangular coil of 50 turns, each side 0.10 m, rotates in a uniform magnetic field of magnitude \(0.20\ \text{T}\). The coil's axis of rotation is perpendicular to the field. The coil is pulled by a force that causes its speed to increase uniformly from rest to \(4.0\ \text{m\,s}^{-1}\) over a distance of \(0.80\ \text{m}\), then moves at constant speed \(4.0\ \text{m\,s}^{-1}\) for a further \(0.80\ \text{m}\), after which it decelerates uniformly to rest over a distance of \(0.40\ \text{m}\). The coil is connected across a resistor of \(10\ \Omega\). (a) Find the total electrical energy dissipated in the resistor during the whole motion. (b) Find the average power dissipated while the coil moves at constant speed.