Two uniform cylindrical wires of the same material and length are connected in series. The first wire has resistance R R\,R and diameter ddd. The second wire has diameter d3\displaystyle \frac{d}{3}3d. Both wires are at the same temperature.
What is the total resistance of the combination?
109R\frac{10}{9}R910R
4R4R4R
9R9R9R
10R10R10R
36 exam-style questions on AQA A Level Physics Current electricity, covering Basics of electricity, Current-voltage characteristics, Resistivity, Circuits, Potential divider, and Electromotive force and internal resistance. Each one has a worked solution and a mark scheme showing where the marks go.