Unit 1 Topic 3 Quiz

The power of an electrical appliance is:
1. the total energy it uses, measured in joules
2. the rate at which it uses energy, measured in watts.
3. the rate at which it uses energy, measured in joules.
4. the total energy it uses, measured in watts
1 watt is:
1. 1 kilowatt-hour (kWh)
2. 1 joule (J)
3. 1joule per second (J/s)
4. 1000 kilowatts (kW)
An electric drill performs the following useful energy transformation:
1. electrical energy to kinetic energy
2. kinetic energy into electrical energy
3. electrical energy into sound
4. heat into electrical energy
When working out how much energy an applaince uses, you have to make sure that:
1. the power is in watts and the time is in hours
2. the power is in kilowatts and the time is in hours.
3. the power is in kilowatts and the time is in seconds.
4. the power is in watts and the time is in seconds.
A "unit" of electricity is measured in:
1. kilowatts per hour
2. kilowatt hours
3. amp hours
4. joules
A 2000 watt fan heater is run for 45 minutes. If electricity costs 8 p per unit, the cost is:
1. £7200
2. £120
3. £7.20
4. £0.12
A step up transformer does the following job:
1. Increases the voltage and increases the current.
2. Decreases the voltage and increases the current.
3. Decreases the voltage and decreases the current
4. Increases the voltage and decreases the current.
Electricity in the National Grid is at a High Voltage. The best reasons for this is:
1. The currect is low, so the wires don't get hot.
2. The current is high, so more electricity gets through.
3. It's cheaper to make lighter wires.
4. Light wires don't look so ugly in the landscape.
The mains voltage in our homes is:
1. 230 V
2. 415 V
3. 11 000 V
4. 275 000 V
Which one of the following statements is correct about the National Grid.
1. The cables are all underground
2. It is designed so that if one part fails, electricity flows around by other lines.
3. It transmits electricity at very high currents.
4. It operates at a safe voltage.