Electricity in the home, Electrical power

Question 1

How does the current move in A.C supply?

Answer 1

The current is constantly changing direction.

Question 2

What are the two types of electrical supplies?

Answer 2

1) A.C supply (Alternating current)
2) D.C supply ( Direct current)

Question 3

What is the potential difference of the Uk mains supply?

Answer 3

230V

Question 4

What is the frequency of A.C?

Answer 4

50 Hz

Question 5

How does the current move in D.C supply?

Answer 5

The current that is always moving in one direction and at constant value.w

Question 6

What are the three wires that connect electrical appliances to the mains supply?

Answer 6

1) Live wire
2) Earth wire
3) Neutral wire

Question 7

What colour are the three wires?

Answer 7

1) Live wire - Brown
2) Earth wire - Yellow/Green
3) Neutral wire - Blue

Question 8

What voltage is the live wire at?

Answer 8

230v

Question 9

What happens if you touch a live wire?

Answer 9

You will die/ get an electric shock

Question 10

How does the live wire work?

Answer 10

It takes current from the mains to the appliance.

Question 11

What happens if a live wire doesnt have a fuse?

Answer 11

A high current from the mains will melt or blow the fuse.

Question 12

What does a fuse do?

Answer 12

The fuse breaks the circuit if a fault in an appliance causes too much current to flow.

Question 13

What causes an electrical shock?

Answer 13

If the live wire is at 230v. Your body and the earth is at 0V. if you touch the live wire a large potential difference is produced across your body and a current flows through you to earth and can cause a large electrical shock.The body provides a low resistance pathway for the current to flow.

Question 14

Efficiency equation?

Answer 14

Efficiency = Power output
——————— x 100
total input energy

Question 15

What is the correlation between energy power and time?

Answer 15

Energy = power x time

Power = Energy
———–
time

Question 16

What is the equation that links potential difference charge and energy transferred

Answer 16

E = QV (Energy transferred = charge flow x potential difference)

Question 17

Which one of the wires inside a plug is there to make an appliance with a metal case safer to use?

Answer 17

Earth wire

Question 18

Explain what happens when too much current passes through a fuse?

Answer 18

The wire heats up and eventually the circuit is broken.

Question 19

The socket is switched off and the iron is unplugged. Explain whether there is still a danger of the man receiving an electrical shock from the plug socket.

Answer 19

Yes there is as the live wire is still open and he reciveves a shock due too the difference in the potential between the live and the ground.

Question 20

State two purposes of insulation that covers the live wire.

Answer 20

Prevents a short circuit and makes it safe so you don’t have a shock