Neco 2025 Physics Question 28

A circular coil of radius \(0.08\ \text{m}\) and total resistance \(4\ \Omega\) rotates in a uniform magnetic field of magnitude \(0.6\ \text{T}\). The axis of rotation lies in the plane of the coil (i.e., the coil rotates about a diameter). The coil makes \(120\) revolutions per minute and the maximum emf induced across its terminals is measured to be \(5.0\ \text{V}\). Assuming the coil has \(N\) turns, determine (a) the number of turns \(N\) (rounded to the nearest whole turn), (b) the induced current when the emf is maximum, and (c) the maximum magnetic torque required to keep the coil rotating at constant speed. Give the torque in newton‑metres to two decimal places.