An electron moving in a circular orbit of radius $r$ makes $n$ rotation per second. The magnetic field produced at the centre has a magnitude of
$\frac{{{\mu _0}ne}}{{2r}}$
$\frac{{{\mu _0}{n^2}e}}{{2r}}$
$\frac{{{\mu _0}ne}}{{2\pi r}}$
Zero
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 straight wire carrying a current $10\, A$ is bent into a semicircular arc of radius $5\, cm.$ The magnitude of magnetic field at the center is
Current $i$ is passed as shown in diagram. If radius of the circle is a, then the magnetic flux density at the centre $P$ will be:
An electron is revolving round a proton, producing a magnetic field of $16\, weber/m^2$ in a circular orbit of radius $1\,\mathop A\limits^o $. It’s angular velocity will be
Write Biot-Savart law.