$A$ straight wire carrying a current $10\, A$ is bent into a semicircular arc of radius $5\, cm.$ The magnitude of the magnetic field at the center is

Consider two thin identical conducting wires covered with very thin insulating material. One of the wires is bent into a loop and produces a magnetic field $B_1$ at its centre when a current $I$ passes through it. The second wire is bent into a coil with three identical loops adjacent to each other and produces a magnetic field $B_2$ at the centre of the loops when a current $I/3$ passes through it. The ratio $B_1 : B_2$ is

What will be the resultant magnetic field at the origin due to four infinite length wires? If each wire produces a magnetic field '$B$' at the origin.

$A$ current of $I$ $A$ is passed through a straight wire of length $2.0$ $m$. The magnetic field at a point in air at a distance of $3$ $m$ from either end of the wire and lying on the axis of the wire will be:

Two concentric rings are kept in the same plane. The number of turns in each ring is $25$. Their radii are $50 \text{ cm}$ and $200 \text{ cm}$,and they carry electric currents of $0.1 \text{ A}$ and $0.2 \text{ A}$ respectively in mutually opposite directions. The magnitude of the magnetic field produced at their centre is . . . . . . $\text{T}$.

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 $P(0, 0, d)\,m$?