Question

A rectangular loop of wire, supporting a mass $m$, hangs with one end in a uniform magnetic field $\vec{B}$ pointing out of the plane of the paper. A clockwise current is set up such that $i>mg/Ba$, where $a$ is the width of the loop. Then :

• A. The weight rises due to a vertical force caused by the magnetic field and work is done on the system
• B. The weight do not rise due to vertical for caused by the magnetic field and work is done on the system
• C. The weight rises due to a vertical force caused by the magnetic field but no work is done on the system
• D. The weight rises due to a vertical force caused by the magnetic field and work is extracted from the magnetic field

Answer 1

Answer: (C)

Correct answer is (c) The weight rises due to a vertical force caused by the magnetic field but no work is done on the system