The magnetic field on the axis of a circular loop of radius $100\,cm$ carrying current $I=\sqrt{2}\,A$, at point $1\,m$ away from the centre of the loop is given by
$3.14 \times 10^{-7}\,T$
$6.28 \times 10^{-7}\,T$
$3.14 \times 10^{-4}\,T$
$6.28 \times 10^{-4}\,T$
Two concentric coplanar circular loops of radii ${r_1}$ and ${r_2}$ carry currents of respectively ${i_1}$ and ${i_2}$ in opposite directions (one clockwise and the other anticlockwise.) The magnetic induction at the centre of the loops is half that due to ${i_1}$ alone at the centre. If ${r_2} = 2{r_1}.$ the value of ${I_2}/{I_1}$ is....
When a certain length of wire is turned into one circular loop, the magnetic induction at the centre of coil due to some current flowing is ${B_1}$ If the same wire is turned into three loops to make a circular coil, the magnetic induction at the center of this coil for the same current will be
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 very long wire $ABDMNDC$ is shown in figure carrying current $I. AB$ and $BC$ parts are straight, long and at right angle. At $D$ wire forms a circular turn $DMND$ of radius $R. AB.$ $\mathrm{BC}$ parts are tangential to circular turn at $\mathrm{N}$ and $D$. Magnetic field at the centre of circle is