In the above figure magnetic field at point $C$ will be
$\frac{{{\mu _0}i}}{{2\pi r}}\left[ {\left( {1 + \pi } \right)\hat k + \hat i} \right]$
$\frac{{{\mu _0}i}}{{4\pi r}}\left[ {\left( {1 + \pi } \right)\hat k - \hat i} \right]$
$\frac{{{\mu _0}i}}{{2\pi r}}\left[ {\left( {1 + \pi } \right)\hat k - \hat i} \right]$
$\frac{{{\mu _0}i}}{{4\pi r}}\left[ {\left( {1 - \pi } \right)\hat k + \hat i} \right]$
The earth’s magnetic field at a given point is $0.5 \times {10^{ - 5}}\,Wb{\rm{ - }}{m^{ - 2}}$. This field is to be annulled by magnetic induction at the center of a circular conducting loop of radius $5.0\,cm$. The current required to be flown in the loop is nearly......$A$
A part of a long wire carrying a current $i$ is bent into a circle of radius $r$ as shown in figure. The net magnetic field at the centre $O$ of the circular loop is
Magnetic fields at two points on the axis of a circular coil at a distance of $0.05\, m$ and $0.2\, m$ from the centre are in the ratio $8: 1.$ The radius of coil is .......... $m$
Magnetic field at the centre $O$ due to the given structure is
A long, straight wire is turned into a loop of radius $10\,cm$ (see figure). If a current of $8\, A$ is passed through the loop, then the value of the magnetic field and its direction at the centre $C$ of the loop shall be close to