Let $m$ and $r$ are the dipole moment and radius of earth respectively. Then, the earth's magnetic field at the equator is

A circular coil consists 70 closely wound turns and has a radius of 10 cm . An externally produced magnetic field of magnitude $2 \times 10^{-3} \mathrm{~T}$ is applied perpendicular to the coil. The net flux through the coil is found to vanish when the current in the coil is 2.2 A . The inductance of the coil is

The $L-C-R$ circuit shown below is driven by an ideal AC voltage source.

At frequency $f=\frac{1}{2 \pi \sqrt{L C}}$, choose the correct statement.

At an instant, a plane electromagnetic wave has its magnetic field in the direction of the vector $\hat{\mathbf{i}}-\hat{\mathbf{j}}$ and its electric field is in the direction of $\hat{\mathbf{i}}+\hat{\mathbf{j}}$. The wave is travelling along which direction?