CAPE Physics Unit 2 · 2006 · Paper 2 · Question 5(b)(ii)

A current balance consists of a 10\text{ cm} section of wire on an electronic balance and a parallel wire directly above it at a separation of 2.5\text{ cm}. When switched on, the reading increases by 5.0 \times 10^{-6}\text{ N}.

The sensitivity of the balance is 0.1 \times 10^{-6}\text{ N}. Calculate the minimum current detectable using this balance.

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