Question

A printer is connected to a 1.0 m cable. if the magnetic force is 9.1 × x10-5 n, and the magnetic field is 1.3 × 10-4 t, what is the current in the cable

Answer 1

The magnetic force on a current-carrying wire due to a magnetic field is given by
$F=ILB$
where
I is the current
L the wire length
B the magnetic field strength

In our problem, L=1.0 m, $F=9.1 \cdot 10^{-5} N$ and $B=1.3 \cdot 10^{-4}T$, so we can re-arrange the formula to find the current in the wire:
$I= \frac{F}{LB}= \frac{9.1 \cdot 10^{-5} N}{(1.0 m)(1.3 \cdot 10^{-4} T)} =0.7 A$