A.c. and d.c. circuits

Question 1

What is Direct current?

Answer 1

An electric current in a wire is a flow of electrons. The current supplied by the cells and batteries is direct current (d.c.). In direct current all the electrons flow in the same direction

Question 2

What is the oscilloscope trace for d.c. ?

Answer 2

A horizontal line

Question 3

What is Alternating current?

Answer 3

Main electricity supplies to homes and businesses is an alternating current (a.c.). Alternating current is an electric current that changes direction regularly, and its potential difference is constantly changing.

Question 4

What is the mains supply’s average voltage and frequency?

Answer 4

230V and 50Hz. This means that the electric current and voltage change direction 100 times every second.

Question 5

What can both d.c. and a.c. be used to transfer?

Answer 5

Both can be used by devices to transfer energy to motors and heating devices

Question 6

What does the power rating tell you?

Answer 6

how much energy is transferred by the appliance each second

Question 7

What is the power rating of a kettle?

Answer 7

2200 W

Question 8

What is the power rating of a hairdryer?

Answer 8

1500W

Question 9

What is the power rating of a microwave?

Answer 9

850W

Question 10

What is the power rating of an electric oven?

Answer 10

3000W

Question 11

What is the power rating of an electric shaver?

Answer 11

15W