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

Potential difference and power — practice question

A cell has an electromotive force (e.m.f.) of $6\,\text{V}$ and internal resistance $R$. An external resistor, also with resistance $R$, is connected across the cell, as illustrated. Power $P$ is dissipated in the external resistor. The cell is then swapped for another cell with an e.m.f. of $6\,\text{V}$ and negligible internal resistance. What is the new power dissipated in the external resistor?

  • A$0.5P$
  • B$P$
  • C$2P$
  • D$4P$

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