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Energy and Electricity
What is the approximate voltage produced by power stations?
Why are transformers used in the National Grid?
Less energy is lost from wires at a high voltage.
Less energy is lost from wires at a low voltage.
They are needed to convert dc electricity into ac electricity.
A transformer produces 100 V from an input of 50 V. What does this tell you?
It is very efficient.
It is a step-up transformer.
It is a step-down transformer.
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?