The diagram below is a simplified representation of an AC generator - NSC Physical Sciences - Question 9 - 2021 - Paper 1

Component Y allows the slip rings to rotate while maintaining contact with the external circuit, thus facilitating the transfer of current to the external circuit.

According to the principle of electromagnetic induction, an emf is induced in the coil as a result of the change in the magnetic field. When the coil rotates, there is a change in the magnetic flux linked with the coil, causing a current to flow. This principle is governed by Faraday's law of electromagnetic induction, which states that the induced emf is directly proportional to the rate of change of magnetic flux.

When the coil rotates clockwise, the induced current in segment PQ will flow from 'P to Q'.

From the graph, the time t indicated is 0.02 s, which corresponds to the period of the wave, calculated as follows: T = 1/f = 1/50 Hz = 0.02 s.

The energy dissipated can be calculated using the formula:

$W = P imes t$

Where power P can be calculated using Ohm's law: $P = I_{rms}^2 imes R$.

Given that the RMS voltage $V_{rms} = \frac{V_{max}}{\sqrt{2}} = \frac{311}{\sqrt{2}} \approx 219.71 \text{ V}$, we can find the current $I_{rms}$:

$I_{rms} = \frac{V_{rms}}{R} = \frac{219.71}{100} = 2.1971 \text{ A}$.

Thus, $P = I_{rms}^2 \times R = (2.1971)^2 \times 100 \approx 483.605 \text{ W}$.

For ONE minute (60 seconds), the energy is: $W = 483.605 \text{ W} \times 60 \text{ s} \approx 28983.3 \text{ J}$.