Paper 2 Alternating Current Drills

Q1 Sinusoidal Voltage

An ac supply has voltage $V=24\sin (200\pi t)$.

1. State the peak voltage. [1]
2. Calculate the frequency. [2]
3. Calculate the rms voltage. [2]

Q2 AC Power in a Resistor

A $18\Omega$ resistor is connected to a sinusoidal supply of rms voltage $12.0\mathrm{V}$.

1. Calculate rms current. [2]
2. Calculate mean power dissipated. [2]
3. Explain why rms values are used for heating calculations. [2]

Q3 Rectification

1. Distinguish alternating input from rectified output. [2]
2. Explain why rectified output is not necessarily steady dc. [2]
3. State the role of a smoothing capacitor. [1]