Magnetism and Matter · Physics · MHT CET

The work done in turning a magnet of magnetic moment ' $M$ ' by an angle of $90^{\circ}$ from the meridian is ' $n$ ' times the corresponding Work done to turn it through an angle of $60^{\circ}$ where the value of ' $n$ ' is $\left(\cos 90^{\circ}=0, \cos 60^{\circ}=0.5\right)$

A bar of iron having magnetic moment $2.4 \mathrm{Am}^2$ weighs 66 g . If the density of the material of the bar is $7700 \mathrm{~kg} / \mathrm{m}^3$, the intensity of magnetisation in $\mathrm{Am}^{-1}$ is

To protect the instrument from magnetic field, it is completely surrounded by

Susceptibility of a paramagnetic substance is

The space within the current carrying toroid is filled with aluminium of susceptibility ' $\chi$ '. The percentage increase in the magnetic field ' $B$ ' will be

Two bar magnets A and B are geometrically similar but the magnetic moment of $A$ is twice that of $B$. $T_1$ is the time period of oscillation when their like poles are kept together. When unlike poles are kept together, the time period of oscillation is $T_2$. The ratio $T_1: T_2$ will be

The magnetic susceptibility of iron is 5499 . The relative permeability of iron will be

If $M$ is the magnetisation induced in the material, H is the magnetic field intensity, B is the net magnetic field inside the material then the correct relation between them is ( $\mu_0=$ permeability of free space)

A solenoid having 400 turns per metre has a core of a material with relative permeability 400. When a current of 0.5 A is passed through it, the magnetization of the core material in $\mathrm{Am}^{-1}$ is nearly

The materials having negative magnetic susceptibility are

A bar magnet has length 4 cm , cross-sectional area $2 \mathrm{~cm}^2$ and magnetic moment $6 \mathrm{Am}^2$. The intensity of magnetisation of bar magnet is

In the following graph of flux density versus magnetizing force, coercivity and retentivity are respectively represented by the points

The correct relation between total magnetic field $(B)$, magnetic intensity $(\mathrm{H})$, permeability of free space $\left(\mu_0\right)$ and susceptibility $(\chi)$ is

A magnetic intensity of $500 \mathrm{~A} / \mathrm{m}$, produces a magnetic flux of $2.4 \times 10^{-5} \mathrm{~Wb}$ in an iron bar of cross-sectional area $0.4 \mathrm{~cm}^2$. The magnetic permeability of the iron bar is

The magnetic moments associated with two closely wound circular coils A and B of radius $r_A=10 \mathrm{~cm}$ and $r_B=20 \mathrm{~cm}$ respectively are equal if $\left(N_A, I_A\right.$ and $N_B, I_B$ are number of turns and current of A and B respectively)

The magnetic susceptibility of the material of a rod is 599. The absolute permeability of the material of the rod will be [ $\mu_0=4 \pi \times 10^{-7}$ SI unit]

A magnetic needle of magnetic moment $6 \times 10^{-2} \mathrm{Am}^2$ and moment of inertia $9.6 \times 10^{-5} \mathrm{~kg} \mathrm{~m}^2$ performs simple harmonic motion in a magnetic field of 0.01 T . Time taken to complete 10 oscillations is [Take $\pi=3 \cdot 14$]

The relation between total magnetic field (B), magnetic intensity $(\mathrm{H})$, permeability of free space $\left(\mu_0\right)$ and susceptibility $(\chi)$ is

A ferromagnetic material is heated above its curie temperature. The correct statement from the following is that

At certain place a magnet makes 30 oscillations per minute. At another place if the magnetic induction is increased by two times the magnetic induction at first place, then the time period of same magnet will be

In the hysteresis curve the value of magnetization (B) which will be present in a substance when value of magnetizing force $$(\mathrm{H})$$ is made zero $$(\mathrm{H}=0)$$ is called as

Magnetic shielding is done by surrounding the instrument to be protected from magnetic field by

For which of the following substances, the magnetic susceptibility is independent of temperature?

A solenoid of 500 turns/m is carrying a current of 3 A. Its core is made of iron which has relative permeability 5001. The magnitude of magnetization is

According to Curie's law in magnetism, the correct relation is ( $$\mathrm{M}=$$ magnetization in paramagnetic sample, $$\mathrm{B}=$$ applied magnetic field, $$\mathrm{T}=$$ absolute temperature of the material, $$\mathrm{C}=$$ curie's constant)

A thin rod of length $$L$$ has magnetic moment $$M$$ when magnetised. If rod is bent in a semicircular arc what is magnetic moment in new shape?

The materials suitable for making electromagnets should have

The magnetic susceptibility of the material of a rod is 349 and permeability of vacuum $$\mu_0$$ is $$4 \pi \times 10^{-7}$$ SI units. Absolute permeability of the material of the rod in SI units is

Two bar magnets '$$\mathrm{P}$$' and '$$\mathrm{Q}$$' are kept in uniform magnetic field '$$\mathrm{B}$$' with magnetic moments '$$\mathrm{M_P}$$' and '$$\mathrm{M_Q}$$' respectively. Magnet 'P' is oscillating with frequency twice that of magnet 'Q'. If the moment of inertia of the magnet 'P' is twice that of magnet 'Q' then

A magnetic dipole of magnetic moment $$\mathrm{M}$$, is freely suspended in a magnetic field of induction B. The minimum and maximum values of potential energy of the dipole, respectively are

A current '$$I$$' is flowing in a conductor of length '$$L$$' when it is bent in the form of a circular loop, its magnetic moment will be

A bar magnet has length $$3 \mathrm{~cm}$$, cross-sectional area $$2 \mathrm{~cm}^2$$ and magnetic moment $$3 \mathrm{~Am}^2$$. The intensity of magnetisation of bar magnet is

The relative permeability of iron is 2000. Its absolute permeability in SI unit will be $$\left(\frac{\mu_0}{4 \pi}=10^{-7} \text{SI unit}\right)$$

The permeability of a metal is $$0.1256 ~\mathrm{TmA}^{-1}$$. Its relative permeability will be $$\mathrm{\left( {{{{\mu _0}} \over {4\pi }} = {{10}^{ - 7}}\,SI\,unit} \right)}$$ ($$\pi=3.14$$)

The north pole of a long horizontal bar magnet is being brought towards closed circuit consisting of a coil. The direction of induced current produced in it is

What is susceptibility of a medium, if its relative permeability is 0.85?

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

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 the domain is

For a paramagnetic substance, the magnetic susceptibility is

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

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 $$\left[\sin 45^{\circ}=\cos 45^{\circ}=\frac{1}{\sqrt{2}}, \sin \frac{\pi}{6}=\frac{1}{2}, \cos \frac{\pi}{6}=\frac{\sqrt{3}}{2}\right]$$

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

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 of free space)

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 permeability of the rod in $$\frac{\mathrm{Wb}}{\mathrm{A}-\mathrm{m}}$$ is

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

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

Magnetic susceptibility of a paramagnetic substance is