Question

A straight horizontal wire of mass 10 mg and length 1.0 m carries a current of 2.0 A. What minimum magnetic field B should be applied in the region, so that the magnetic force on the wire may balance its weight?

Answer 1

The magnetic field of 4.9$\times$10-5 T should be on the region.

Explanation:

Given:

Wire’s mass, M = 10−5 Kg

Wire’s length, l = 1.0 m

Through the wire, the flowing electric current, I = 2.0 A

According to the question, the wire’s weight must be composed by the magnetic force that is acting on the wire. The angle between the magnetic field and the length of the wire is 90°.

So, Mg = IlB, where

g is the gravity’s acceleration = 9.8 m/s2

B is the magnetic field applied

Thus,

B = MgIl = 4.9$\times$10-5 T