Two long parallel conductors $X$ and $Y$ are placed vertically at a distance $d$ apart. Conductor X carries a current I upwards and conductor Y carries a current 21 downwards. A third long conductor Z is placed parallel to both X and Y and between X and Y . If Z carries a current I upwards and is at a distance $x$ from conductor X , then:

A. All the conductors are in equilibrium and the net force on Z is zero

B. The net force on Z is $\frac{\mu_0 I^2}{2 x \pi}\left[\frac{d+x}{d-x}\right]$ towards X

C. The net force on Z is $\frac{\mu_0 I^2}{2 x \pi}\left[\frac{d+x}{d-x}\right]$ towards Y

D. The net force on Z is $\frac{\mu_0 I^2}{2 x \pi}\left[\frac{d-x}{d+x}\right]$ towards Y

A $50 \Omega$ galvanometer is shunted by a resistance of $S \Omega$. If $8 \%$ of total current passes through the galvanometer, the value of $S$ is:

A proton is moving along negative $X$ axis. If a uniform magnetic field is applied parallel to the positive $Z$ axis, then choose the correct answer from the following options;

1. The proton will experience magnetic force along positive Y direction and will move along a circular path in the XY plane

2. The proton will experience magnetic force along negative Y direction and will move along a circular path in the XY plane

3. The proton will experience magnetic force along positive Y direction and will move along a circular path in the XZ plane

4. The proton will experience magnetic force along negative Y direction and will move along a circular path in the XZ plane

The magnetic field at the centre of a wire loop formed by two semicircular wires of radii $r_1=3.14 \mathrm{~m}$ and $r_2=6.28 \mathrm{~m}$ and carrying a current of $\mathrm{I}=2 \mathrm{~A}$ is: