Two infinitely long wires carrying currents of $8\,A$ and $6\,A$ are placed along the $X$-axis and $Y$-axis respectively. What is the magnetic field at point $P(0, 0, d)\,m$?

$A$ long straight wire in the horizontal plane carries a current of $50\, A$ in the north to south direction. Find the magnitude and direction of the magnetic field $B$ at a point $2.5\, m$ east of the wire.

An element $\Delta l = \Delta x \hat{i}$ is placed at the origin and carries a current $I = 10 \,A$. The magnetic field on the $y$-axis at a distance of $0.5 \,m$ from the element of length $\Delta x = 1 \,cm$ is:

$B_{x}$ and $B_{y}$ are the magnetic fields at the center of two coils $x$ and $y$ respectively,each carrying equal current. If coil $x$ has $200$ turns and $20 \ cm$ radius,and coil $y$ has $400$ turns and $20 \ cm$ radius,the ratio of $B_{x}$ and $B_{y}$ is $:-$

The magnetic induction at the centre of a current-carrying circular coil of radius $r$ is

$A$ square frame of side $1 \ m$ carrying a current $I$ produces a magnetic field $B$ at its centre. The same current is passed through a circular coil having the same perimeter as the square. The magnetic field at the centre of the circular coil is $B^{\prime}$. The ratio of $\frac{B}{B^{\prime}}$ is