Physics (AS & A Level) · May / June 2025 · Paper 12 · Question 35

The diagram shows a cell of internal resistance 1.0R connected to a variable resistor. [circuit diagram: cell with internal resistance 1.0R in series with a variable resistor] When the variable resistor has an initial resistance of 2.0R, the current in the cell is I₁ and the terminal potential difference (p.d.) across the cell is V₁. The variable resistor is now adjusted to a new resistance of 4.0R. What is the new current in the cell and the new terminal p.d. across the cell?

1. Acurrent 0.50I₁, terminal p.d. 1.0V₁
2. Bcurrent 0.50I₁, terminal p.d. 1.2V₁
3. Ccurrent 0.60I₁, terminal p.d. 1.0V₁
4. Dcurrent 0.60I₁, terminal p.d. 1.2V₁

As printed in the paper