Figure shows a square loop $ABCD$ with edge length $a$. The resistance of the wire $ABC$ is $r$ and that of $ADC$ is $2r$. The value of magnetic field at the centre of the loop assuming uniform wire is
$\frac{{\sqrt 2 \,{\mu _0}i}}{{3\pi \,a}}\odot$
$\frac{{\sqrt 2 \,{\mu _0}i}}{{3\pi \,a}} \otimes $
$\frac{{\sqrt 2 \,{\mu _0}i}}{{\pi \,a}}\odot$
$\frac{{\sqrt 2 \,{\mu _0}i}}{{\pi \,a}} \otimes $
Find magnetic field at $O$
The magnetic induction at a point $P$ which is distant $4\, cm$ from a long current carrying wire is ${10^{ - 8}}\,Tesla$. The field of induction at a distance $12\, cm $ from the same current would be
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
In figure two parallel infinitely long current carrying wires are shown. If resultant magnetic field at point $A$ is zero. Then determine current $I.$ (in $A$)
A thin wire of length $l$ is carrying a constant current. The wire is bent to form a circular coil. If radius of the coil, thus formed, is equal to $R$ and number of turns in it is equal to $n$, then which of the following graphs represent $(s)$ variation of magnetic field induction $(b)$ at centre of the coil