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The photograph shows a step-down transformer - Edexcel - GCSE Physics - Question 2 - 2014 - Paper 1
Question 2
The photograph shows a step-down transformer. (a) Explain why step-down transformers are used in the transmission of electricity in the National Grid. (b) Transfor... show full transcript
Worked Solution & Example Answer:The photograph shows a step-down transformer - Edexcel - GCSE Physics - Question 2 - 2014 - Paper 1
Step 1
Explain why step-down transformers are used in the transmission of electricity in the National Grid.
Answer
Step-down transformers are essential in the National Grid because they decrease high voltage levels, for instance, reducing voltage from 200,000 V to a more manageable 230 V. This reduction in voltage is crucial for energy efficiency and safety, as transmitting electricity at high voltages minimizes power loss over distances. Moreover, low voltages are safer to handle near homes and factories, thus reducing the risk of electrocution.
Step 2
Sketch a graph of an alternating current with a frequency of 2 Hz.
Answer
To sketch the graph of an alternating current with a frequency of 2 Hz, the graph will consist of a continuous wave that oscillates above and below the x-axis. It needs two complete cycles in 1.0 s, indicating that each cycle lasts 0.5 s. The y-axis is labeled as 'current / A' and the x-axis as 'time / s'. The complete graph will show a sinusoidal wave pattern, with maximum and minimum values of 2 A and -2 A respectively.