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Energy and efficiency
The energy transferred by an electrical appliance can be calculated using this equation:
energy = power × time
How much energy is transferred by a 500 W electric drill in 30 seconds?
A 250W computer is switched on for 4 hours. How many Units of electricity does it use?
A 2 kW electric fire is switched on for 30 minutes. How many Units of electricity does it use?
If one Unit of electricity costs 10p, how much will 30 Units cost?