Two similar coils are kept mutually perpendicular such that their centres coincide. At the centre, find the ratio of the magnetic field due to one coil and the resultant magnetic field by both coils, if the same current is flown

Apply Biot-Savart law to find the magnetic field due to a circular current carrying loop at a point on the axis of the loop.

Figure shows a square loop $ABCD$ with edge length $a$. The resistance of the wire $ABC$ is $r$ and that of $ADC$ is $2r$. The value of magnetic field at the centre of the loop assuming uniform wire is

In a hydrogen atom, an electron moves in a circular orbit of radius $5.2 \times {10^{ - 11}}\,m$ and produces a magnetic induction of $12.56\, T$ at its nucleus. The current produced by the motion of the electron will be (Given ${\mu _0} = 4\pi \times {10^{ - 7}}\,Wb/A - m)$

$AB$ and $CD$ are long straight conductor, distance $d$ apart, carrying a current $I$. The magnetic field at the midpoint of $BC$ is

The magnetic induction at a point $P$ which is distant $4\, cm$ from a long current carrying wire is ${10^{ - 8}}\,Tesla$. The field of induction at a distance $12\, cm $ from the same current would be