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Figure 6 shows part of the UK National Grid system for the supply of electricity to homes - Edexcel - GCSE Physics Combined Science - Question 3 - 2023 - Paper 2
Question 3
Figure 6 shows part of the UK National Grid system for the supply of electricity to homes. Electricity supplied to homes has a frequency of A 0.02 Hz B 20 Hz C... show full transcript
Worked Solution & Example Answer:Figure 6 shows part of the UK National Grid system for the supply of electricity to homes - Edexcel - GCSE Physics Combined Science - Question 3 - 2023 - Paper 2
Step 1
Step 2
Explain why the National Grid uses high voltages with small currents to transfer electricity from power stations.
Answer
The National Grid uses high voltages for transmission to reduce energy losses. When electricity is transmitted at high voltages, the current flowing through the wires decreases. Since the power loss due to heating in transmission lines is given by the formula:
where (P_{loss}) is the power loss, (I) is the current, and (R) is the resistance of the transmission line, reducing the current considerably decreases the power lost during transmission. Therefore, high voltage transmission is more efficient, resulting in lower energy costs and less waste.