Calculate the energy used by a 40 W light bulb in 2 minutes.
The energy used in a 40 W light bulb in 2 minutes: Energy transferred = power x time = 40 W x 120 s = 4800 J
1 of 18
Calculate the cost of running a 2 kW heater for 4 hours if the electricity company charges 15p per unit (kWh).
The cost of running a 2 kW heater for two hours: Cost = power in kW x time in hours x cost of 1 kW 2 x 4 x 0.15 = £1.20
2 of 18
When considering energy costs what is meant by the term 'payback time'?
Payback time is the number of years it takes to get back the cost of an appliance from the money it saves on energy bills.
3 of 18
Equation for efficiency of a device.
Efficiency = useful energy transferred by the device/total energy supplied x 100
4 of 18
Why should we use the most efficient household appliances?
We should use the most efficient household appliances because the more efficient they are the less energy we waste and the more money we save.
5 of 18
Explain the term electromagnetic induction.
A current is always induced when there is a relative movement between a magnet and coil of wire. This is electromagnetic induction.
6 of 18
Give three factors that affect the size of the induced current in a generator.
Three factors that affect the size of the induced current in a generator are the strength of the magnetic, the number of coils in the wire and the speed at which the magnet is moving.
7 of 18
Give three ways that turbines can be made into power stations.
Three ways in which turbines can be turned into power stations are by using wind, moving water, steam under high pressure.
8 of 18
Name the non-renewable energy source.
Fossil fuels and nuclear fuels are the non-renewable energy sources.
9 of 18
What are the disadvantages of using nuclear power.
The disadvantages of nuclear power are it is very expensive to build and decommission nuclear power stations and they have the longest start-up time. Nuclear waste is also very dangerous for thousands of years and hard to get rid of.
10 of 18
Name two polluting gases produced by burning coal.
Carbon dioxide and Sulphur dioxide are produced by burning coal.
11 of 18
Give an advantage of solar power.
An advantage of solar power is that individual homes can generate their own electricity which is particularly useful in remote places.
12 of 18
Give a disadvantage of solar power.
A disadvantage of solar power is that is does not work at night or cloudy days.
13 of 18
What are the disadvantages of wind power?
The disadvantages of wind power are that it only works when there is wind. Wind turbines also spoil the view and cause noise pollution.
14 of 18
What does a step-up transformer do?
A step-up transformer converts the input voltage into a higher output voltage and reduces the current at the same time.
15 of 18
In the National Grid why is electrical energy transferred at very high voltages?
In the national grid electrical energy is transmitted at very high voltages because it improves efficiency by reducing the current and therefore heat loss in transmission lines. This makes it less expensive to transmit energy.
16 of 18
Explain how ionising radiation is dangerous to the body.
Ionising radiation is dangerous to the body because they cause ionisation inside cells. Increased exposure to ionising radiation increases damage to living cells, eventually leading to cancer or cell death.
17 of 18
Why is radioactive contamination more dangerous than a short period of irradiation?
Radioactive contamination is more dangerous than a short period of irradiation because the person is exposed to ionising radiation for a longer period of time.
18 of 18
Other cards in this set
Card 2
Front
Calculate the cost of running a 2 kW heater for 4 hours if the electricity company charges 15p per unit (kWh).
Back
The cost of running a 2 kW heater for two hours: Cost = power in kW x time in hours x cost of 1 kW 2 x 4 x 0.15 = £1.20
Card 3
Front
When considering energy costs what is meant by the term 'payback time'?
Back
Card 4
Front
Equation for efficiency of a device.
Back
Card 5
Front
Why should we use the most efficient household appliances?
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