Question 2
(a) State one difference between direct current and alternating current.
(b) Fig. 1 is a series RL circuit. 
Calculate the:
(a) inductive reactance;
(b) impedance;
(c) phase angle.
The expected responses were:
Differences between direct current and alternating current
Direct currentAlternating current
Has steady magnitude/amplitude
Varies in magnitude/amplitude
Does not change in polarity
Periodically changes in polarity
Has no frequency
Has frequency
