A Helmholtz coil has pair of loops, each with $N$ turns and radius $R$. They are placed coaxially at distance $R$ and the same current $I$ flows through the loops in the same direction. The magnitude of magnetic field at $P$, midway between the centres $A$ and $C$, is given by (Refer to figure)
$\frac{{4N{\mu _0}I}}{{{5^{3/2}}R}}$
$\frac{{8N{\mu _0}I}}{{{5^{3/2}}R}}$
$\frac{{4N{\mu _0}I}}{{{5^{1/2}}R}}$
$\frac{{8N{\mu _0}I}}{{{5^{1/2}}R}}$
A straight wire of diameter $0.5\, mm$ carrying a current of $1\, A$ is replaced by another wire of $1\, mm$ diameter carrying the same current. The strength of magnetic field far away is
In the figure, find out the magnetic field at $B$ (Given $I =2.5 \;A,r =5\, cm )$
Find the magnetic field at point $P$ due to a straight line segment $AB$ of length $6\, cm$ carrying a current of $5\, A$. (See figure) $(\mu _0 = 4p\times10^{-7}\, N-A^{-2})$
Magnetic fields at two points on the axis of a circular coil at a distance of $0.05\, m$ and $0.2\, m$ from the centre are in the ratio $8: 1.$ The radius of coil is .......... $m$
A circular current carrying coil has a radius $R$. The distance from the centre of the coil on the axis where the magnetic induction will be $\frac{1}{8}^{th}$ to its value at the centre of the coil, is