Question Constellation Sign up for free AQA · GCSE · Combined Science · Higher
Step-up transformers and network efficiency
A network of transformers and transmission cables transfers electrical power from power stations to consumers.
Explain how using step-up transformers makes the network efficient.
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Marking points
- 1 State that step-up transformers increase the potential difference.
- 2 State that increasing potential difference reduces the current.
- 3 Link the smaller current to less energy loss in the transmission cables or to the surroundings.
Full-mark answer
Step-up transformers increase the potential difference in the transmission cables. For the same power transfer this reduces the current, so less energy is transferred to the surroundings by heating and the network is more efficient.
Why this answer loses marks
They increase the voltage so less energy is lost.
This gives the start and end of the explanation but misses the required link that the current is reduced.