Physics Magnetism and Matter

Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties of the following, which property best matches for the type of magnet required?

An iron rod of volume ${10}^{-3}{\mathrm{m}}^3$ ${}^{}{}^{}$ and relative permeability 1000 is placed as core in a solenoid with 10 turns/cm. If a current of $0.5\mathrm{A}$ $$ is passed through the solenoid, then the magnetic moment of the rod will be:

The figure gives experimentally measured $B$ vs $\mathrm{H}$  variation in a ferromagnetic material. The retentivity, co-ercivity and saturation, respectively, of the material are

Two infinite planes each with uniform surface charge density +σ are kept in such a way that the angle between them is 30°. The electric field in the region shown between them is given by:

(A)
(B)
(C)
(D)

A bar magnet of length 14 cm is placed in the magnetic meridian with its north pole pointing towards the geographic north pole. A neutral point is obtained at a distance of 18 cm from the centre of the magnet. If BH = 0.4G, the magnetic moment of the magnet is 1G = 10^-4T

In a uniform magnetic field, the magnetic needle has a magnetic moment 9.85 * 10?² A/m² and moment of inertia 5 * 10? kg m². If it performs 10 complete oscillations in 5 seconds then the magnitude of the magnetic field is _______ mT. [Take π² as 9.85]

The value of aluminium susceptibility is 2.2 * 10?. The percentage increase in the magnetic field if space within a current carrying toroid is filled with Aluminium is x/10?. Then the value of x is _______.

A soft ferromagnetic  material is placed in an external magnetic field. The magnetic domains:

In a ferromagnetic region with zero magnetization.

An iron bar of length $L$ has magnetic moment $M$ . It is bent at the middle of its length such that the two arms make an angle $60^{?}$  with each other. The magnetic moment of this new magnet is :