Mathematics

Problem

A straight copper wire

0.50\,\text{m}

long has a mass of

25\,\text{g}

. It is hung horizontally in a uniform vertical magnetic field of

0.20\,\text{T}

. Calculate the current required in the wire so that the magnetic force just balances its weight. (Take

g = 9.8\,\text{m s}^{-2}