Chapter 17: Practical Electricty Flashcards
1
Q
Electrical energy —> Thermal energy
A
Electrical energy —> thermal energy via heating elements in heating appliances such as electric radiator, electric iron, electric hotplate and electric kettle
2
Q
Power
A
P = VI = I^2R = V^2 / R
3
Q
Energy
A
E = VIt = I^2Rt = V^2 / R t
4
Q
Dangers of electricity
A
- Damaged insulation
- Overheating of cables
- Damp environments
5
Q
Overheating of cables
A
- Overloaded power sockets
2. Use of inappropriate wires
6
Q
Safety features
A
- Circuit breakers
- Fuses
- Switches
- Earthing
- Thee-pin plug
- Double insulation
7
Q
Live wire
A
Brown
240V
Circuit breakers, fuses and switches are fitted
8
Q
Neutral wire
A
Blue
0V
9
Q
Earth wire
A
Green and yellow
Low-resistance
10
Q
Double insulation
A
- Internal components
2. External casing
11
Q
Why should the earth wire be connected to the metal casing
A
If the live wire breaks and touches the metal casing, the earth wire carries the current away and prevents the user from getting an electric shock
