P1.3

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  • Created by: elisha.ks
  • Created on: 07-03-17 18:44
what do electrical appliances do
transfer electrical energy into other forms really quickly
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what does the amount of energy that's transferred by an appliance depend on
its power and amount of time the appliance is switched on
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units for energy, power and time (1)
kWh (kilowatt-hours), kW (kilowatt), h (hour)
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units for energy, power and time (2)
J (Joules), W (Watts), s (seconds)
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what is a kilowatt-hour
amount of electrical energy used by a 1kW appliance left on for 1hours
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formulas for calculating cost of electricity
1)units= power x time 2) cost= no. of units x price per unit
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how to calculate total energy used over a particular time from meter readings
subtract meter reading at start from end
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advantages/ disadvantages of battery radios
good for areas with no mains electricity supply/ batteries expensive and need replacing, energy and chemicals to make batteries so bad for environment and hard to dispose of safely
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advantages/disadvantages of clockwork radios
good for areas with no mains electricity supply, free, store elastic potential energy in a spring then slowly released to power radio, better for environment/ keep winding up every few hrs to recharge
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what does access to electricity affect/ difference between countries
standard of living/ most in developed have access to mains electricity, in poorer countries they dont
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what do refrigerators do
keep food fresh for longer, slow down bacteria growth, keep vaccines cold - without its difficult to distribute important vaccines so could have bad effect on populations
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how does electricity help improve public health
hospitals in developed rely on it (eg xray machines), enables diagnosis and treatment of patients so increases life expectancy
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how does electricity affect communication
lack of it means no phones or internet to send/receive news or information
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Other cards in this set

Card 2

Front

what does the amount of energy that's transferred by an appliance depend on

Back

its power and amount of time the appliance is switched on

Card 3

Front

units for energy, power and time (1)

Back

Preview of the front of card 3

Card 4

Front

units for energy, power and time (2)

Back

Preview of the front of card 4

Card 5

Front

what is a kilowatt-hour

Back

Preview of the front of card 5
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