Two wires, X and Y, made from different metals, are connected in parallel across a power supply of negligible internal resistance.
Wire X has length LLL, diameter ddd, and the mean drift velocity of electrons in it is 0.45 mm s-1. Wire Y has length 2.5L, diameter 1.5d1.5d1.5d, and the mean drift velocity of electrons in it is vvv.
The metal of wire Y has a charge carrier number density that is 1.5 times that of wire X, and a resistivity that is 0.8 times that of wire X.
What is the mean drift velocity v v\,v of the electrons in wire Y?
0.067 mm s−10.067\text{ mm s}^{-1}0.067 mm s−1
0.15 mm s−10.15\text{ mm s}^{-1}0.15 mm s−1
0.34 mm s−10.34\text{ mm s}^{-1}0.34 mm s−1
1.35 mm s−11.35\text{ mm s}^{-1}1.35 mm s−1
5 exam-style questions on OCR A A Level Physics Charge and current, covering Charge and Mean drift velocity. Each one has a worked solution and a mark scheme showing where the marks go.