$A$ rectangular coil $ABCD$ is hung from one side of a balance as shown in the figure. $A$ $500 \, g$ mass is added to the other arm to balance the weight of the coil. $A$ current of $9.8 \, A$ is passed through the coil and a constant magnetic field of $0.4 \, T$ acting inward is switched on such that only arm $CD$ of length $1.5 \, cm$ lies in the field. The additional mass $m$ that must be added to regain the balance is: (in $, g$)

$A$ wire carrying a current $i$ is placed in a uniform magnetic field $B$ in the form of the curve $y = a \sin \left( \frac{\pi x}{L} \right)$,where $0 \leq x \leq 2L$. The magnetic force on the wire is

$A$ conducting loop carrying a current $I$ is placed in a uniform magnetic field pointing into the plane of the paper as shown. The loop will have a tendency to

What is the net force on the loop shown in the figure?

The circuit in the 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 $10 \, g$ and is $5 \, cm$ long. The wire is hanging as shown in the figure. The springs stretch $0.5 \, cm$ 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 $0.3 \, cm$. The magnetic field is

Two straight parallel wires,both carrying $10 \ A$ in the same direction,attract each other with a force of $1 \times 10^{-3} \ N$. If both currents are doubled,the force of attraction will be: