Answer to Question #258875 in Electricity and Magnetism for Anthony

Question

Consider the following situation shown below. A mass, m = 1.8 kg, is hung from a conducting wire shaped into a loop. The dimensions of the loop are 2m x 1.8m. Part of the loop is in a region where a uniform magnetic field (B = 1.6T) is into the page everywhere.

If there were a current in the wire loop,

a) which direction would the current have to flow in order for the wire to be at rest and not fall? Show your work and explain your reasoning.

b) what would the magnitude of the current have to be in order for the wire

This link below provides the picture for this question.

https://dropmefiles.com/7SMOw

Answer 1

a) The current in the loop should flow in such a direction that it would produce the Ampere's force in the direction opposite to the force of gravity, therefore, the current in the loop should flow to the left according to the left hand rule, and the direction of the current must be clockwise:

b) The force must be equal to the force of gravity:

$$F_A=IBL=mg,\\\space\\ I=mg/(BL)=5.5\text{ A}.$$