Physics - Magnetism Question with Solution | TestHub

The circuit in figure consists of wires at the top and bottom and identical springs as the left and right sides. The wire at the bottom has a mass of $10\mathrm{g}$ and is $5\mathrm{cm}$ long. The wire is hanging as shown in the figure. The springs stretch $0.5\mathrm{cm}$ under the weight of the wire and the circuit has a total resistance of $12\Omega$. When the lower wire is subjected to a static magnetic field, the springs, stretch an additional $0.3\mathrm{cm}$. The magnetic field is