Answer to Question #181361 in Electricity and Magnetism for Daisy

Question

A conductive wire 23.5cm long is dipped in a magnetic field B, which is per- pendicular to the wire. A current i = 3.5A travels the wire and a force F = 2.2 · 10−4N acts on it.

Compute the value of the magnetic field B.

The circled dots indicate that the magnetic field is exiting from the plane of the paper

Answer 1

Answer

Force is given by

F=lLBsin$\theta$

So magnetic field is given

$B=\frac{F}{lLsin\theta}\\=\frac{2.2\times10^{-4}}{3.5\times 0.235\times sin90°}\\=2.67\times10^{-4}T$