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 fig with current connection shown, the magnetic field at the centre of the square is zero in cases

An electron in a hydrogen atom revolves around its nucleus with a speed of $6.76 \times 10^6\,ms ^{-1}$ in an orbit of radius $0.52\,\mathring A$. The magnetic field produced at the nucleus of the hydrogen atom is $......T$.

Find out magnetic field at point $O$ ?

The radius of a circular current carrying coil is $R$. At what distance from the centre of the coil on its axis, the intensity of magnetic field will be $\frac{1}{2 \sqrt{2}}$ times that at the centre?

When a certain length of wire is turned into one circular loop, the magnetic induction at the centre of coil due to some current flowing is ${B_1}$ If the same wire is turned into three loops to make a circular coil, the magnetic induction at the center of this coil for the same current will be

A current loop consists of two identical semicircular parts each of radius $R,$ one lying in the $x-y$ plane and the other in $x-z$ plane. If the current in the loop is $i.$ The resultant magnetic field due to the two semicircular parts at their common centre is