Magnetism and Matter

A domain in a ferromagnetic substance is in the form of a cube of side $1 \mu \mathrm{~m}$. If it contains $8 \times 10^{10}$ atoms and each atomic dipole has a dipole moment of $9 \times 10^{-24} \mathrm{Am}^2$, then the magnetisation of t...

A steel wire of length / has a magnetic moment $M$. It is then bent into a semicircular arc. The new magnetic moment is

An iron rod is placed parallel to magnetic field of intensity \(2000 \mathrm{~A} / \mathrm{m}\). The magnetic flux through the rod is \(6 \times 10^{-4} \mathrm{~Wb}\) and its cross-sectional area is \(3 \mathrm{~cm}^2\). The magnetic perme...

Two identical bar magnets each of magnetic moment \(M\), separated by some distance are kept perpendicular to each other. The magnetic induction at a point at the same distance \(d\) from the centre of magnets, is (\(\mu_0=\) permeability o...

A thin light weight rod of diamagnetic substance such as silver is suspended in uniform external magnetic field. It will align itself with its length

If the angle of dip at places \(A\) and \(B\) are \(30^{\circ}\) and \(45^{\circ}\) respectively, then the ratio of horizontal component of earth's magnetic field at \(A\) to that at \(B\) will be $$\left[\sin 45^{\circ}=\cos 45^{\circ}=\fr...

The magnetic susceptibility of a paramagnetic material at \(-73^{\circ} \mathrm{C}\) is 0.0075. Its value at \(-173^{\circ} \mathrm{C}\) will be

A magnetizing field of $5000 \mathrm{~A} / \mathrm{m}$ produces a magnetic flux of $4 \times 10^{-5} \mathrm{~Wb}$ in an iron rod of cross-sectional area $0.4 \mathrm{~cm}^2$. The permeabilit of the rod in Wb/A-m, is

Magnetic susceptibility of a paramagnetic substance is

The magnetization of bar magnet of length 5 cm , cross sectional area $2 \mathrm{~cm}^2$ and net magnetic moment $1 \mathrm{Am}^2$ is