The magnitude of the magnetic field at the center of an equilateral triangular loop of side $1 \ m$ which is carrying a current of $10 \ A$ is $.... \mu T$.

$A$ wire carrying current $i$ is shaped as shown. Section $AB$ is a quarter circle of radius $r$. The magnetic field at the center $C$ is directed:

Two parallel wires carry currents $i_1$ and $i_2$ $(i_1 > i_2)$. When the currents are in the same direction,the magnetic field at a point midway between the wires is $10 \, \mu T$. When the direction of $i_2$ is reversed,the magnetic field at that point becomes $30 \, \mu T$. What is the ratio $\frac{i_1}{i_2}$?

Define the intensity of magnetic field.

If a positive ion is moving away from an observer with some acceleration,then the lines of force of magnetic induction will be

An infinite number of straight wires,each carrying current $I$,are equally placed as shown in the figure. Adjacent wires have current in opposite directions. The net magnetic field at point $P$ is: