Magnetism and Matter

For a current-carrying loop, the magnetic field lines near the wire are nearly:

What happens to the spacing between magnetic field lines as you move away from a bar magnet?

The tangent to a magnetic field line at any point gives the direction of _____ at that point.

The work done in moving a magnetic pole around a closed magnetic field line is:

A bar magnet is placed on a horizontal table such that its magnetic North pole points towards the Earth's geographic South. A student maps the resultant magnetic field lines. In this specific orientation, the 'neutral points' where the net magnetic field is zero will be located:

The property that magnetic field lines are continuous through a magnet implies that the flux through any cross-section of the magnet is:

Inside a current-carrying cylindrical wire of radius $R$, at a distance $r < R$ from the axis, the magnetic field lines are circular. How does the density of these lines vary with $r$?

Which of the following best describes the geometry of magnetic field lines inside a current-carrying sheet of infinite extent?

If a bar magnet is heated to a temperature much higher than its Curie point, what is the visual representation of its field lines?

A magnetic field line passes through a region with a time-varying electric field. According to the Maxwell-Ampere law, this time-varying electric field acts as a source for:

A map which shows the lines joining points with the same value of magnetic elements is called a:

In which units is magnetic declination usually measured?

Agonic lines are specific isogonic lines where the magnetic declination is exactly:

What are isogonic lines?

A dip circle is used to measure:

The horizontal component of the Earth's magnetic field at a place is $B_H$. A bar magnet of length $L$ and pole strength $m$ is placed in the magnetic meridian with its North pole pointing North. The distance of the neutral point from the center of the magnet is $d$. Which relation holds (assuming $d \gg L$)?

As we move from the magnetic equator to the magnetic north pole, the angle of dip:

The value of the total magnetic field of the Earth is $0.4\,G$ at a place where the dip is $30^\circ$. The vertical component of the field is:

A bar magnet of moment $M$ is placed with its North pole pointing South. If the neutral point is at a distance $r$ from the center on the axial line, then:

If the angle of dip is $I$ and the latitude is $\lambda$, the relationship $\tan I = 2 \tan \lambda$ is derived from:

The susceptibility of a paramagnetic material at temperature $T_1$ is $\chi_1$. If the temperature changes to $T_2$, the new susceptibility $\chi_2$ is:

Which substance has a magnetic susceptibility that is independent of both the external field strength and temperature?

Small packets of atoms aligned in the same direction in ferromagnetic materials are called:

The relative permeability of vacuum is:

Which of these materials is likely to have a very wide hysteresis loop?

The SI unit of intensity of magnetization ($M$) is:

Which of the following is true for a diamagnetic substance?

In the Weiss Molecular Field Theory, the spontaneous alignment of magnetic moments in ferromagnetic materials is explained by an internal 'molecular field' produced by the neighboring dipoles. The total effective magnetic field $H_{eff}$ is the sum of the external field $H$ and the molecular field $H_i = \lambda M$, where $\lambda$ is the molecular field constant and $M$ is the magnetization. Assuming the material obeys the Curie Law $M = \frac{C}{T} H_{eff}$ in the paramagnetic phase, identify the Curie temperature $T_C$ and the resulting expression for magnetic susceptibility $\chi$ for $T > T_C$.

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

A substance is placed in a non-uniform magnetic field. If it experiences a force towards the region of the stronger field, the substance could be:

Which physical quantity has the unit $J/T$?

The torque acting on a magnetic dipole of moment $M$ in a field $B$ is zero when the dipole is:

As we move away from a bar magnet along its axis, the magnetic field strength:

The expression for the time period of a vibration magnetometer is:

A short bar magnet has a magnetic moment $M$. What is the magnitude of the magnetic field at a point $P$ located at a distance $r$ from the center of the magnet, such that the line joining the center to $P$ makes an angle of $60^\circ$ with the magnetic axis?

A magnetic dipole of moment $M$ is initially aligned with a uniform magnetic field $B$. If the dipole is rotated by $180^\circ$ so that it reaches its unstable equilibrium position, what is the change in the potential energy of the dipole?

A bar magnet is placed in a uniform magnetic field $B$. The work done in rotating the magnet from its stable equilibrium position to a position where its axis makes an angle of $60^\circ$ with the field is $W$. What is the magnitude of the torque acting on the magnet at this $60^\circ$ position?

A short bar magnet of magnetic moment $\vec{M}$ is placed at the origin with its axis aligned along the x-axis. A point $P$ is located at a distance $r$ from the origin such that the position vector $\vec{r}$ makes an angle $\theta$ with the x-axis. If the resultant magnetic field $\vec{B}$ at point $P$ is found to be perpendicular to the magnetic moment $\vec{M}$ of the magnet, find the value of $\theta$.

If a bar magnet is placed with its North pole facing South, the neutral points are on the:

The ratio of the magnetic moment of a solenoid of $N$ turns, area $A$ and current $I$ to a bar magnet of pole strength $m$ and length $L$ is given by:

Magnetic Intensity $H$ is also known as:

If magnetic susceptibility $\chi = -1$, the relative permeability $\mu_r$ is:

Which material has the highest susceptibility?

The magnetic induction $B$ inside a solenoid with a core of relative permeability $\mu_r$ is:

Which of the following relations is correct for the units of the quantities involved?

What is the magnetic intensity $H$ produced by a current of $2\,A$ in a solenoid of length $50\,cm$ with $500$ turns?

The slope of the $B-H$ curve for a vacuum is equal to:

For a paramagnetic substance, if the magnetic field is tripled and the absolute temperature is tripled, the magnetisation will:

The Bohr magneton is the:

An electron moving in a circular orbit of radius $r$ with frequency $f$ has a magnetic moment $m$ equal to: