TRANSFORMERS AND NATIONAL GRIDS

2 marks · Easy

The transmission lines carry electricity at a low current. Give two reasons why this is an advantage in the National Grid.

(a)

Reason 1:

[1 mark]

(b)

Reason 2:

[1 mark]

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(a) Reduces energy losses as heat in the cables.

(b) Allows thinner (or cheaper) cables to be used.

Common mistakes: Saying it makes voltage higher

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Marking points

B1 (a) · 1 mark · States that low current reduces heat/energy loss.

B1 (b) · 1 mark · States other valid reason, e.g., thinner wires/cables can be used or is cheaper/safer.

Worked solution

a) Low current results in less energy lost as heat (since ).

b) Thinner and lighter cables can be used, making transmission cheaper.