CAPE Physics Unit 2 · 2005 · Paper 1 · Question 1(b)(i)

A current of 0.10 A flows through a copper wire of diameter 0.10 x 10^-3 m and then through a salt solution in a glass tube of diameter 0.010 m. The density of conduction electrons in copper is 1.1 x 10^29 m^-3. The current in the solution is carried equally by positive and negative ions with charges 2e, and the concentration of each ion species is 6.1 x 10^23 m^-3.

Calculate the number of electrons passing through the wire each second.

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