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KS4 Electricity – Buying Electricity. Buying electricity. In your home will be an electricity meter. It records how much electricity you use in units. From the number of units you use your electricity bill is calculated. 26. How many units have been used here? ______. 06895674. 06895702.
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Buying electricity In your home will be an electricity meter. It records how much electricity you use in units. From the number of units you use your electricity bill is calculated. 26 How many units have been used here? ______ 06895674 06895702
Cost of electricity The cost of electricity is the number of units multiplied by the cost per unit: Cost = Number of units x cost per unit Example: How much would 10 units of electricity cost at a price of 9p per unit? Cost = 10 x 9p = 90 p
What is one unit of electricity? Energy = Power x time Units: kWh 1 unit of electricity = 1 kWh Example: How many units of electricity is 17.6 kWh? 17.6 units
Buying electricity – question 1: A kettle uses 45.2 kWhr of energy. If electricity costs 10p per unit, how much does it cost to use the kettle? Number of units: Number of units of electricity is 45.2 units Cost of electricity: Cost = 45.2 x 10 p = 452p or £4.52
Buying electricity - question 2: An iron that operates at a power of 3 KW for 4 hours uses electricity that costs 8p per unit. How much does it cost for the electricity that it uses? Number of units: kWhr = 3kW x 4hr = 12 kWhr Number of units of electricity is 12 units Cost of electricity: Cost = 12 x 8 p = 96p