Flashcards
Fuels for power
Flashcards do conjunto (14)
- 1What do electrical appliances usually display a power rating in?Electrical appliances usually display a power rating in watts (W) or kilowatts (kW).
- 2What is the word equation for power by voltage?power = voltage x current
- 3PRACTICE QUESTION What is the power rating of a kettle working at 9 amps (A) on the mains supply of 230 volts (V)?power = voltage x current
power = 9 x 230
power = 2070 W - 4What is the word equation for energy supplied by power?energy supplied = power x time
- 5What is the unit of electrical energy used in the home?The unit for electrical energy used in the home is the kilowatt-hour (kWh).
- 6What is the word equation for cost of electricity used by energy used?cost of electricity used = energy used x cost per kWh
- 7PRACTICE QUESTION Calculate the cost of using a 250 W television for 30 minutes if one kWh of electricity costs 10p?energy used = power x time
energy used = 0.25 x 0.5
energy used = 0.125 kWh
cost of electricity = energy used x cost per kWh
cost of electricity = 0.125 x 10
cost of electricity = 1.25p - 8Why do we pay less for electricity during the night?We pay less for electricity during the night when not as much is needed, but it still has to be produced.
- 9Some energy sources are more appropriate than others in a particular situation. The choice of energy sources depends on which several factors?The choice of energy sources depends on several factors:
- availability
- ease of extraction
- effect on the environment
- associated risks. - 10What is the National Grid?The National Grid is a series of transformers and power lines that transport electricity from the power station to the consumer.
- 11In the National Grid what are transformers used for?In the National Grid, transformers are used to step up the voltage to as high as 400 000 V.
- 12What does the high voltage lead to?The high voltage leads to:
- reduced energy loss
- reduced distribution costs
- cheaper electricity for consumers. - 13What are transformers then used again for?Transformers are then used again to step down the voltage to a more suitable level for the consumer.
- 14When a current passes through a wire the wire gets hot. The greater the current, the hotter the wire: - what happens when a transformer increases the voltage?- when a transformer increases the voltage, the current is reduced which means there is less heating effect and therefore less energy is lost to the environment.
Informações
- Descrição
- GCSE Science Year 10 FlashCards sobre Fuels for power, criado por annjb2898 em 01-06-2014.
- Criado por
- annjb2898 · jun 2014
- Atualizado
- 19 fev 2016
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