A metal rod of mass $10 \mathrm{gm}$ and length $25 \mathrm{cm}$ is suspended on two springs as shown in the figure. The springs are extended by $4 \mathrm{cm}$. When a $20 \mathrm{ampere}$ current passes through the rod it rises by $1 \mathrm{cm}$. Determine the magnetic field assuming acceleration due to gravity to be $10 \mathrm{m} {\mathrm{s}}^{-2}$.

The magnetic field at point $P$ due to given current distribution:-

A circular conducting loop is connected by a battery according to the figure. The length of $ABC$ and $ADC$ is ${𝓁}_1$ and ${𝓁}_2$, respectively, then which is correct:-

Two thick wires and two thin wires, all of the same materials and same length form a square in the three different ways $P$, $Q$ and $R$ as shown in the figure with the current connection shown. The magnetic field at the centre of the square is zero in cases:-

The equation of a line on which magnetic field is zero due to a system of two perpendicular infinitely long current carrying straight wires is:

In the given figure magnetic field at the centre of ring $\left(O\right)$ is $8\sqrt{2} \mathrm{T}$. Now it is through $90°$ about $XX\text{'}$ axis, so that two semicircular parts are mutually perpendicular. Then find the value of a magnetic field in $\mathrm{Tesla}$) at centre: