CAPE Physics Unit 2 · 2017 · Paper 1 · Question Q2

Item 2 refers to the following diagram. [Diagram of a cylindrical conductor of length l, cross-sectional area A, with electrons moving inside] The conductor shown above has n free electrons per unit volume, each carrying a charge, e. The electron drift velocity is v. The equation used to calculate the current, I, flowing in the conductor is

1. (A)I = n e v A
2. (B)I = n e l A
3. (C)I = n e v A^2
4. (D)I = n e v A l

This question uses a figure or table from the paper — you'll see it when you practise.