In the figure, shown the magnetic induction at the centre of there $arc$ due to the current in portion $AB$ will be
$\frac{{{\mu _0}i}}{r}$
$\frac{{{\mu _0}i}}{{2r}}$
$\frac{{{\mu _0}i}}{{4r}}$
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 $({\mu _0} = 4\pi \times {10^{ - 7}}\,Wb/A.m)$
A Rowland ring of mean radius $15\; cm\;3500$ turns of wire wound on a ferromagnetic core of relative permeability $800.$ What is the magnetic field $B$ (in $T$) in the core for a magnetizing current of $1.2\; A?$
If induction of magnetic field at a point is $B$ and energy density is $U$ then which of the following graphs is correct
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: