Magnetism and Matter · Physics · TS EAMCET
MCQ (Single Correct Answer)
At a certain place in the magnetic meridian the Earth's magnetic field is twice its vertical component. The ratio of horizontal component of Earth's magnetic field and the total magnetic field of the Earth at the place is
A short bar magnet of magnetic moment $2.5 \mathrm{Am}^2$ is kept in a uniform magnetic field of $4 \times 10^{-5} \mathrm{~T}$. The work done in moving the magnet from its most stable position to most unstable position is
The magnetic field at a point $P$ on the axis of a short bar magnet of magnetic moment $M$ is $B$. If another short bar magnet of magnetic moment 2 M is placed on the first magnet such that their axes are perpendicular and their centres coincide. The resultant magnetic field at the point $P$ due to both the magnets is
If $B_V$ and $B_H$ are respectively the vertical and horizontal components of the Earth's magnetic field at a place where the angle of $\operatorname{dip}$ is $60^{\circ}$, then the total magnetic field at that place is
If the magnetic susceptibility of a substance is 0.6 , then the ratio of permeability of the substance and permeability of free space is
A bar magnet of magnetic moment $2 \mathrm{~A}-\mathrm{m}^2$ lies aligned with the direction of a uniform magnetic field of 0.3 T . The amount of work required by an external torque to turn the magnet so as to align its magnetic moment normal to the field direction is
If $\chi$ is the susceptibility and $\mu_r$ is the relative permeability of a ferromagnetic substance, then
The period of oscillation of a bar magnet at a place is 2 s . At the same place, the period of oscillation of another identical bar magnet whose magnetic moment is 4 times so that of first magnet is
materials suitable for permanent magnets, must have which of the following properties?
The expression for the magnetic energy stored in a solenoid of length $L$, in terms of magnetic field $B$ and area $A$ is
The magnetic susceptibility of ferromagnetic materials is
In the magnetic meridian of a certain place, the horizontal component of the earth's magnetic field is 86.6 G (Gauss) and the magnetic field of earth is 100 G (Gauss). The the dip angle is
An iron bar having a cross-sectional area of $2 \times 10^{-5} \mathrm{~m}^2$ and magnetising field of $2400 \mathrm{~A} / \mathrm{m}$ produce a magnetic flux $2.4 \pi \times 10^{-5} \mathrm{~Wb}$. What will be the value of permeability $\mu$ and susceptibility $\chi$ of the bar (given, $\mu_0=4 \pi \times 10^{-7}$ )
The magnitude of axial field due to a bar magnet at a distance of 1 m , is found to be $5 \times 10^{-8} \mathrm{~T}$. The magnetic moment of the bar magnet is $\left(\mu_0=4 \pi \times 10^{-7}\right)$
A thin magnetic needle is placed in a magnetic field of 200 G with its axis at $30^{\circ}$ to the direction of the field. Find the magnetic moment of the needle, if it experiences a torque of 0.012 Nm in this field.
A planet has magnetic dipole moment of $27 \times 10^{22} \mathrm{~A}-\mathrm{m}^2$. If the radius of the planet is 300 km , what would be the magnetic field at its equator? $\left(\right.$ use,$\left.\frac{\mu}{4 \pi}=10^{-7}\right)$
Which of the following is desirable for making permanent magnets?
A short bar magnet placed with its axis at $30^{\circ}$ with an external field of 800 G experiences a torque of 0.016 Nm . The magnetic moment of the bar magnet is
A solenoid has a core of a material with relative permeability $\frac{800}{\pi}$. The windings of the solenoid are insulated from the core and carry current of 2 A . If the number of turns is 1000 per metre, find the magnetic field $B$.
Let $m$ and $r$ are the dipole moment and radius of earth respectively. Then, the earth's magnetic field at the equator is
Two short magnets of equal dipole moments $M$ are fastened perpendicularly at their centres which lies at origin. Let two magnets lie along $X$-axis and $Y$-axis, respectively.
The magnitude of the magnetic field at a distance $R$ from the centre on the $Y$-axis is $\frac{\mu_0}{4 \pi} \frac{M_0}{R^3}$. Assuming, $R \gg l$ (magnet length), the magnitude of $M$ is
If relative permeability of iron is 5500 , then its susceptibility is