Paper 3 Alternating Current Drills

Q1 RMS from a Sinusoid

A sinusoidal current has peak value $5.0\mathrm{A}$ and flows through a $6.0\Omega$ resistor.

1. Calculate the rms current. [2]
2. Calculate the mean power dissipated. [2]
3. Explain why using the arithmetic mean current would give the wrong heating result. [3]

Q2 AC Waveform Quantities

An oscilloscope shows a sinusoidal voltage with peak-to-peak value $40\mathrm{V}$ and period $8.0\mathrm{ms}$.

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