The magnetic induction at the centre of a current carrying circular coil of radius $10\, cm$ is $5\sqrt 5 \,times$ the magnetic induction at a point on its axis. The distance of the point from the centre of the coil (in $cm$) is
$5$
$10$
$20$
$25$
Find the magnetic field at the point $P$ in figure. The curved portion is a semicircle connected to two long straight wires.
The magnetic field at the centre of a wire loop formed by two semicircular wires of radii $R_1=2 \pi\ \mathrm{m}$ and $R_2=4 \pi\ \mathrm{m}$ carrying current $I=4 \mathrm{~A}$ as per figure given below is $\alpha \times 10^{-7} \mathrm{~T}$. The value of $\alpha$ is___________ (Centre $\mathrm{O}$ is common for all segments)
A regular polygon of $6$ sides is formed by bending
a wire of length $4 \pi$ meter. If an electric current of $4 \pi \sqrt{3} \mathrm{~A}$ is flowing through the sides of the polygon, the magnetic field at the centre of the polygon would be $x \times 10^{7} \mathrm{~T}$. The value of $\mathrm{x}$ is______.
A closely wound flat circular coil of $25$ $turns$ of wire has diameter of $10\, cm$ and carries a current of $4\, ampere$. Determine the flux density at the centre of a coil
Find out magnetic field at point $O$ ?