Alternating Current

Question 1

The root-mean-square (r.m.s.) value of an alternating current

Answer 1

For an a.c waveform, the r.m.s value of the current is the value of the direct current that would give the same heating effect as using alternating current in the same resistor.

Question 2

Link Io and Irms

Link Vo and Vr.m.s

Answer 2

Irms = Io/√2
Vrms = Vo/√2

Question 3

UK mains info

Answer 3

Uses alternating currents
Frequency = 50Hz
Vrms = 230V

Question 4

Why do UK mains use a.c

Answer 4

UK mains use a.c because transformers only work with a.c and the voltage has to be stepped up at the power station and then transported through the national grid without severe heat loss.