Magnetism and matter practice · Mixed difficulty

At a point on the right bisector of a magnetic dipole magnetic

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?

Assertion: Ferro-magnetic substances become paramagnetic below Curie temp.
Reason : Domains are destroyed at high temperature

The unit of permeability of Vacuum $\left(\mu_0\right)$ is ______

A magnet is dropped down in infinitely long vertical
copper tube.

Given below are two statements; one is labeled as Assertion A and the other is labeled as Reason R.

Assertion (A) : Electromagnets are made of soft iron.

Reason (R) : soft iron has high permeability and low retentivity.

In the light of above, statements, choose the most appropriate answer from the options given below.

The values of the apparent angles of dip in two planes at right angles to each other are $30^{\circ}$ and $45^{\circ}$. Calculate the true value of the angle of dip at the place.

A bar magnet is oscillating in the Earth’s magnetic field with a period $T$. What happens to its period of motion if its mass is quadrupled?

The value of magnetic susceptibility $\chi$ of a paramagnetic sample can be represented by ($\Delta$ being a small quantity)

An inductor of 10 mH shows 50 mH when operate with a core mad e of ferrite. The susceptibility of ferrite is

Assertion (A): Magnetism is relativistic.

Reason (R): When we move along with the charge, so that there is no motion relative to us, we find no magnetic field associated with the charge.

For a diamagnetic substance (symbols have their usual meanings)

At the magnetic poles of the earth, a compass needle will be

The magnetic lines of force, produces due to a
bar magnet

In a superconductor, critical magnetic field

Assertion(A): $\chi-T$ graph for a diamagnetic material is a straight line parallel to $T$ - axis.

Reason (R): This is because susceptibility of a diamagnetic material is not affected by temperature.

A short bar magnet of magnetic moment $0.4\, \mathrm{J\,T}^{-1}$ is placed in a uniform magnetic field of $0.16 \mathrm{~T}$. The magnet is stable equilibrium when the potential energy is :

At which place, earth’s magnetism becomes horizontal

The susceptibility of a paramagnetic material is $K$ at 27$^ \circ C$. At what temperature will its susceptibility be $K/2$?

Which of the following represents correct formula for magnetic flux?

A paramagnetic material is kept in a magnetic field. The field is increased till the magnetisation becomes constant. If the temperature is now decreased, the magnetisation

Assertion (A): Magnetic moment of helium atom is zero.

Reason (R): All the electron are paired in helium atom orbitals.

The angle between the true geographic north
and the north shown by a compass needle is
called as

A deflection magnetometer is adjusted in the usual way. When a magnet is introduced, the deflection observed is $\;\mathrm{\theta }$, and the period of oscillation of the needle in the magnetometer is $T$. When the magnet is removed, the period of oscillation is ${T_0}.$ The relation between $T$ and ${T_0}$ is

The susceptibility of a magnetism at $300 \mathrm{~K}$ is $1.2 \times 10^{-5}$. The temperature at which susceptibility increases to $1.8 \times 10^{-5}$ is

A light wave travelling linearly in a medium of dielectric constant 4, incidents on the horizontal interface separating medium with air. The angle of incidence for which the total intensity of incident wave will be reflected back into the same medium will be:
(Given : relative permeability of medium ${\mu _r} = 1)$

The field due to a magnet at a distance $R$ from the centre of the magnet is proportional to

A magnet is placed on a paper in a horizontal plane for locating neutral points. $A$ dip needle placed at the neutral point will be horizontal at the

Which of the following statements is incorrect about hysteresis

Ferromagnetic materials used in a transformer must have