Magnetism and matter practice · Mixed difficulty

A short magnet produces a deflection of $37^{\circ}$ in a deflection magnetometer in Tan- $A$ position when placed at a separation of $10 \mathrm{~cm}$ from the needle. Find the ratio of the magnetic moment of the magnet to the earth's horizontal magnetic field (in $\mathrm{~A-m}^2 \mathrm{~T}^{-1}$).

Permanent magnets are those substances that ________.

The presence of magnetic field can be
determined using which one of the following
instruments?

If the magnetizing field on a ferromagnetic material is increased, its permeability

Two short bar magnets of moments ' $M$ ' and $\sqrt{3} M^{\prime}$ are joined like a cross (+) This cross suspended from its centre with its plane horizontal in the earth's magnetic field. When the cross comes to equilibrium, angle made by the weaker magnet with the earth's magnetic field $B_H$ is

A magnet is parallel to a uniform magnetic field. If it is rotated by $60^\circ$, the work done is $0.8\;J$. How much work is done in moving it $30^\circ$ further

The intensity of magnetic field due to an isolated pole of strength $m$ at a point distance $r$ from it will be

Which of the following is responsible for the earth's magnetic field?

Curie law $\chi T=$ constant, relating magnetic susceptibility $(\chi)$ and absolute temperature (T) of magnetic substances, is obeyed by

Which of the following statements are correct?
A. Electric monopoles do not exist, whereas magnetic monopoles exist.
B. Magnetic field lines due to a solenoid at its ends and outside cannot be completely straight and confined.
C. Magnetic field lines are completely confined within a toroid.
D. Magnetic field lines inside a bar magnet are not parallel.
E. $\chi = - 1$ is the condition for a perfect diamagnetic material, where $\chi$ is its magnetic susceptibility.
Choose the correct answer from the options given below.

For a vibration magnetometer, the time period of suspended bar magnet can be reduced by

A bar magnet is $0.10 \mathrm{~m}$ long and its pole strength is $12\,\mathrm{Am}$. Find the magnitude of the magnetic field at a point on its axis at a distance of $20 \mathrm{~cm}$ from it.

A magnetic field strength $(\mathrm{H}) 3 \times 10^3 \mathrm{Am}^{-1}$ produces a magnetic field of induction (B) of $12 \pi \mathrm{T}$ in an iron rod. Find the relative permeability of iron?

The resultant magnetic moment of neon atom will be

Assertion (A): The properties of paramagnetic and ferromagnetic substance are not effected by heating.

Reason (R): As temperature rises, the alignment of molecular magnets gradually increases.

Permanent magnet has properties retentivity and coercivity respectively

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 magnet of magnetic moment $M$ is rotated through $360^\circ$ in a magnetic field $H$. The work done will be

An electron in an atom revolves around the nucleus in an orbit of radius 0.5 Å. Calculate the equivalent magnetic moment if the frequency of revolution of the electron is $10^{10}\,\mathrm{MHz}$.

Assertion: Magnetic susceptibility of diamagnetic substance is small negative.
Reason: Diamagnetic substance have unpaired electron.

A magnet of magnetic moment $50\hat i\;A$-${m^2}$ is placed along the $x$-axis in a magnetic field $\vec B = \left( {0.5\;\hat i + 3.0\hat j} \right)T$. The torque acting on the magnet is

Identify the paramagnetic substance:

The relationship between the magnetic susceptibility $(\chi )$ and the magnetic permeability $(\mu)$ is given by:

$(\mu_0$ is the permeability of free space and $\mu_r$ is relative permeability)

Which of the following material is not
ferromagnetic in nature?

Assertion (A): Magnetic moment of an atom is due to both, the orbital motion and spin motion of every electron.

Reason (R): A charged particle at rest produces a magnetic field.

Which one of the following characteristics is
not associated with a paramagnetic material?

At any place on earth, the horizontal component of earth's magnetic field is $\sqrt{3}$ times the vertical component. The angle of dip at that place will be

Statement I Time period of oscillation of two magnets, when like poles are in same direction (in a vibration magnetometer) is smaller, than the period of vibration when like poles are in opposite direction.

Statement II Moment of inertia increases in same position.
In the light of the above statements, choose the most appropriate answer from the options given below.

The susceptibility of certain magnetic material is 5000 . What is the class of magnetic material?

Lines passing through points of zero declination is