Physics 9702 · AS & A Level · Potential difference and power

Potential difference and power — practice question

An electric railway locomotive produces a peak mechanical output power of $4.0\,\text{MW}$. It receives electrical power at $25\,\text{kV}$ through overhead wires. The locomotive’s overall efficiency in changing electrical power into mechanical power is $80\%$. What current is drawn from the overhead wires when the locomotive is running at maximum power?

  • A$130\,\text{A}$
  • B$160\,\text{A}$
  • C$200\,\text{A}$
  • D$250\,\text{A}$

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