PLEASE HELP PHYSICS EXAM An energy input of 1.3 × 1018 J is supplied each year by power stations to the National Grid.

Not all of this energy is supplied to consumers. Some of the energy is wasted in the distribution process.

Write the equation which links efficiency, total input energy transfer and useful output

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energy transfer.

The energy supplied each year to consumers is 1.2 × 1018 J Calculate the efficiency of the distribution process.

[1 mark]