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

Potential difference and power — practice question

For the circuit diagram below, lamp P is rated $250\,\text{V},\,50\,\text{W}$ and lamp Q is rated $250\,\text{V},\,200\,\text{W}$. Both lamps are joined in series to a $250\,\text{V}$ power supply. Take the resistance of each lamp to be constant. Which statement most accurately describes what happens when the switch is closed?

  • ALamp P emits four times as much power as lamp Q.
  • BLamp P emits twice as much power as lamp Q.
  • CLamp Q emits four times as much power as lamp P.
  • DLamp Q emits twice as much power as lamp P.

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