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

Given

Weight is mg= 0.80 N

Magnetic field B=2.50 T

Length is L=0.050 m

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The magnetic force on the wire must be balanced with the weight of the wire. So,

$BIL=mg$

The current passing through the wire is

$I=\frac{mg}{BL}=\frac{0.80 N}{(2.50 T)(0.050 m)}=6.4 A$