Question

A wire of length 0.050 𝑚 and carries a current 𝐼 is in a horizontal uniform magnetic field B of 2.50 𝑇 which is perpendicular to the rod. The weight of the wire is 0.80 𝑁. What is the value of the current 𝐼 if the magnetic force on the wire equals its weight? 

Answer 1

$F_A=IBl,$

$F_A=P,\implies$

$I=\frac{P}{Bl},$

$I=\frac{0.8}{2.5\cdot 0.05}=6.4~A.$