Each atom of an iron bar $(5\,cm \times 1\,cm \times 1\,cm)$ has a magnetic moment $1.8 \times {10^{ - 23}}\,A{m^2}.$ Knowing that the density of iron is $7.78 \times {10^3}\,k{g^{ - 3}}\,m,$ atomic weight is $56$ and Avogadro's number is $6.02 \times {10^{23}}$ the magnetic moment of bar in the state of magnetic saturation will be.....$A{m^2}$
$4.75$
$5.74$
$7.54$
$75.4$
Write the difference between electric field lines and magnetic field lines.
The field due to a magnet at a distance $ R$ from the centre of the magnet is proportional to
A magnetic needle suspended horizontally by an unspun silk fibre, oscillates in the horizontal plane because of the restoring force originating mainly from
The magnetic lines of force inside a bar magnet
The ultimate individual unit of magnetism in any magnet is called