Neco Model Questions Vol1 2024 Physics Question 4

A rectangular coil of \(N=200\) turns and area \(A=0.020\) m\(^2\) rotates at a constant angular speed \(\omega\) in a uniform magnetic field of magnitude \(B=0.50\) T. The average emf induced during a quarter turn (from \(\theta=0\) to \(\theta=\pi/2\)) is measured to be 5.0 V.\n(a) Determine the angular speed \(\omega\) in rad·s\(^{-1}\).\n(b) If the coil is connected to a resistor of \(R=10\) \(\Omega\), find the maximum current that flows in the circuit.\n(c) Using the maximum current, calculate the mechanical power required to keep the coil rotating, assuming the only torque is the magnetic torque \(\tau = N I A B \sin\theta\) evaluated at the instant of maximum current (\(\theta=90^{\circ}\)). Give the power in watts.