Two infinitely long wires each carrying current $I$ along the same direction are made into the geometry as shown in the figure below. The magnetic field at the point $P$ is
$\frac{\mu_0 I}{\pi r}$
$\frac{\mu_0 I}{r}\left(\frac{1}{\pi}+\frac{1}{4}\right)$
zero
$\frac{\mu_0 I}{2 \pi r}$
The magnetic field at the centre of a circular current carrying-conductor of radius $r$ is $B_c$. The magnetic field on its axis at a distance $r$ from the centre is $B_a$. The value of $B_c$ : $B_a$ will be
A current of $i$ ampere is flowing through each of the bent wires as shown the magnitude and direction of magnetic field at $O$ is
A vertical wire kept in $Z-X$ plane carries a current from $Q$ to $P$ (see figure). The magnetic field due to current will have the direction at the origin $O$ along
A wire in the form of a circular loop of one turn carrying a current produces a magnetic field $B$ at the centre. If the same wire is looped into a coil of two turns and carries the same current, the new value of magnetic induction at the centre is
A parallel plate capacitor of area $60\, cm^2$ and separation $3\, mm$ is charged initially to $90\, \mu C$. If the medium between the plate gets slightly conducting and the plate loses the charge initially at the rate of $2.5\times10^{-8}\, C/s$, then what is the magnetic field between the plates ?