The magnetic field at the centre of a circular coil of radius $r$ is $\pi $ times that due to a long straight wire at a distance $r$ from it, for equal currents. Figure here shows three cases : in all cases the circular part has radius $r$ and straight ones are infinitely long. For same current the $B$ field at the centre $P$ in cases $1$, $2$, $ 3$ have the ratio
$\left( { - \frac{\pi }{2}} \right):\left( {\frac{\pi }{2}} \right):\left( {\frac{{3\pi }}{4} - \frac{1}{2}} \right)$
$\left( { - \frac{\pi }{2} + 1} \right):\left( {\frac{\pi }{2} + 1} \right):\left( {\frac{{3\pi }}{4} + \frac{1}{2}} \right)$
$ - \frac{\pi }{2}:\frac{\pi }{2}:3\frac{\pi }{4}$
$\left( { - \frac{\pi }{2} - 1} \right):\left( {\frac{\pi }{2} - \frac{1}{4}} \right):\left( {\frac{{3\pi }}{4} + \frac{1}{2}} \right)$
There are two infinitely long straight current carrying conductors and they are held at right angles to each other so that their common ends meet at the origin as shown in the figure given below. The ratio of current in both conductor is $1: 1$. The magnetic field at point $P$ is ...... .
Apply Biot-Savart law to find the magnetic field due to a circular current carrying loop at a point on the axis of the loop.
In hydrogen atom, an electron is revolving in the orbit of radius $0.53\,{\mathop A\limits^o }$ with $6.6 \times {10^{15}}$ $rotations/second$. Magnetic field produced at the centre of the orbit is.......$wb/{m^2}$
A current $I$ enters a circular coil of radius $R$, branches into two parts and then recombines as shown in the circuit diagram. The resultant magnetic field at the centre of the coil is
A cell is connected between two points of a uniformly thick circular conductor. The magnetic field at the centre of the loop will be