The magnetic field due to a current carrying square loop of side a at a point located symmetrically at a distance of $a/2$ from its centre (as shown is)
$\frac{{\sqrt 2 \,{\mu _0}i}}{{\sqrt 3 \,\pi \,a}}$
$\frac{{{\mu _0}\,i}}{{\sqrt 6 \,\pi \,a}}$
$\frac{{2\,{\mu _0}i}}{{\sqrt 3 \,\pi \,a}}$
zero
Two concentric coils each of radius equal to $2\pi \,{\rm{ }}cm$ are placed at right angles to each other. $3$ $ampere$ and $4$ $ampere$ are the currents flowing in each coil respectively. The magnetic induction in $Weber/{m^2}$ at the centre of the coils will be $({\mu _0} = 4\pi \times {10^{ - 7}}\,Wb/A.m)$
Given below are two statements:
Statement $(I)$: When an object is placed at the centre of curvature of a concave lens, image is formed at the centre of curvature of the lens on the other side.
Statement $(II)$: Concave lens always forms a virtual and erect image.
In the light of the above statements, choose the correct answer from the options given below:
A cell is connected between the points $A$ and $C$ of a circular conductor $ABCD$ of centre $O$ with angle $AOC = {60^o}$. If ${B_1}$ and ${B_2}$ are the magnitudes of the magnetic fields at $O$ due to the currents in $ABC$ and $ADC$ respectively, the ratio $\frac{{{B_1}}}{{{B_2}}}$ is
Give Oersted’s observation.
Find out magnetic field at point $O$ ?