Magnetism and matter practice · Mixed difficulty

The relative permeability $(\mu_r)$ of a substance is related to its susceptibility $(\chi)$ as

A sample of cast iron exhibits a magnetic field $B=0.5 T,$ when intensity of magnetizing field $(H)$ is $10 \frac{\mathrm{A}}{\mathrm{m}}.$ Relative permeability of iron is 

A bar magnet of length 0.2m and with a magnetic moment of $10\,A{m^2}$ is placed in a uniform magnetic field of intensity 0.8 T, with is axis making an angle of $30^\circ$ with the field. What is the torque on the magnet?

The vertical component of the earth's magnetic field is $6 \times 10^{-5} \mathrm{~T}$ at any place where the angle of dip is $37^{\circ}$. The earth's resultant magnetic field at that place will be
$\left(\right.$ Given $\left.\tan 37^{\circ}=\frac{3}{4}\right)$

Susceptibility of $Mg$ at $300\;K$ is $1.2 \times {10^{ - 5}}$. The temperature at which susceptibility will be $1.8 \times {10^{ - 5}}$is

A dip circle is at right angles to the magnetic meridian.

The area enclosed by a hysteresis loop is a measure of

The magnet can be completely demagnetized by

Given below are two statement:

Statement-I: Susceptibilities of paramagnetic
substances incerase with decrease in temperature.

Statement-II: Diamagnetism is a result of orbital
motions of electrons developing magnetic
moments opposite to the applied magnetic field.

Choose the correct answer from the options given
below.

A magnet is suspended in such a way that it oscillates in the horizontal plane. It makes $20\;oscillations\;per\;minute$ at a place where dip angle is $30^\circ$ and $15\;oscillations\;per$ $minute$ at a place where dip angle $60^\circ$. The ratio of total earth’s magnetic field at the two places is

A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It

Magnetic susceptibility for a paramagnetic and diamagnetic material is respectively

Hysteresis loss is minimized by using

Two magnets of magnetic moments $4\,A{m^2}$ and $3\,A{m^2}$ are joined to form a cross $\left( + \right)$ then the magnetic moment of the combination is $\left[ {A{m^2}} \right]$

A magnetic needle suspended by a silk thread is vibrating in the earth's magnetic field. if the temperature of the needle is increased by $700^{\circ} \mathrm{C}$, then

If a piece of metal was thought to be magnet, which one of the following observations would offer conclusive evidence

Assertion: If a compass needle be kept at magnetic north pole of the earth, the compass needle may stay in any direction
Reason: Dip needle will stay vertical at the north pole of earth.

Magnetic field strength due to a short bar magnet on its axial line at a distance x is B. Its value at the same distance on the equatorial line is

At a place the angle of dip is $30^\circ .$ If the horizontal component of earth’s magnetic field is ${B_H},$ then the total field intensity is

A diamagnetic material in a magnetic field moves

When a ferromagnetic substance is heated to a temperature above its Curie temperature, it:

Consider a short magnetic dipole of magnetic length 10 cm. Its geometric length is

At which place, earth’s magnetism becomes horizontal

At a certain place the angle of dip is $30^{\circ}$ and the horizontal component of earth's magnetic field is $0.5 \,\mathrm{G}$. The earth's total magnetic field (in G), at that certain place, is :

The magnetic induction in air at a distance $d$ from an isolated point pole of strength $m$ unit will be

A long magnet is cut into two equal parts, such that the length of each half is same as that of original magnet. If the period of original magnetic is $T$, the period of new magnet is

If $\mathrm{M}$ is magnetic moment and $\mathrm{B}$ is the magnetic field, then the torque is given by

The magnetic induction and magnetising field intensity in a sample of magnetic material are $\mathrm{B}$ and $\mathrm{H}$ respectively. The magnetic susceptibility of the material is:

Two bar magnets having same geometry with magnetic moments $M$ and $2 M$ are first placed in such a way that their similar poles are same side then its time period of oscillation is $T_1$. Now the polarity of one of the magnet is reversed then the time period of oscillation is $T_2$, so

The period of oscillation of a freely suspended bar magnet is 4 s. If it is cut into two equal parts in length, then the time period of each part will be