Magnetic Properties of Matter

A magnet hung at $45^{\circ}$ with magnetic meridian makes an angle of $60^{\circ}$ with the horizontal. The actual value of the angle of dip is -

An electron with energy 0.1 keV moves at right angle to the earth's magnetic field of 1 $\times$ 10^$-$4 Wbm^$-$2. The frequency of revolution of the electron will be : (Take mass of electron = 9.0 $\times$ 10^$-$31 kg)

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

The space inside a straight current carrying solenoid is filled with a magnetic material having magnetic susceptibility equal to 1.2 $\times$ 10^$-$5. What is fractional increase in the magnetic field inside solenoid with respect to air as medium inside the solenoid?

The susceptibility of a paramagnetic material is 99. The permeability of the material in Wb/A-m, is : [Permeability of free space $\mu$₀ = 4$\pi$ $\times$ 10^$-$7 Wb/A-m]

A magnetic needle lying parallel to a magnetic field requires $W$ units of work to turn it through ${60^ \circ }.$ The torque needed to maintain the needle in this position will be :

The magnetic lines of force inside a bar magnet

Two bar magnets oscillate in a horizontal plane in earth's magnetic field with time periods of $3 \mathrm{~s}$ and $4 \mathrm{~s}$ respectively. If their moments of inertia are in the ratio of $3: 2$, then the ratio of their magnetic moments will be:

A magnetic needle of magnetic moment 6.7 $\times$ 10⁻² A m² and moment of inertia 7.5 $\times$ 10⁻⁶ kg m² is performing simple harmonic oscillations in a magnetic field of 0.01 T. Time taken for 10 complete oscillations is:

The length of a magnet is large compared to its width and breadth. The time period of its oscillation in a vibration magnetometer is $2s.$ The magnet is cut along its length into three equal parts and these parts are then placed on each other with their like poles together. The time period of this combination will be

Two short bar magnets of length $1$ $cm$ each have magnetic moments $1.20$ $A{m^2}$ and $1.00$ $A{m^2}$ respectively. They are placed on a horizontal table parallel to each other with their $N$ poles pointing towards the South. They have a common magnetic equator and are separated by a distance of $20.0$ $cm.$ The value of the resultant horizontal magnetic induction at the mid-point $O$ of the line joining their centres is close to $\left( \, \right.$ Horizontal component of earth's magnetic induction is $3.6 \times 10.5Wb/{m^2})$

A magnet of total magnetic moment 10⁻² ${\widehat i}$ A-m² is placed in a time varying magnetic field, B${\widehat i}$ (cos $\omega t$) where B = 1 Tesla and $\omega$ = 0.125 rad/s. The work done for reversing the direction of the magnetic moment at t = 1 second, is -

A small bar magnet placed with its axis at 30^o with an external field of 0.06 T experiences a torque of 0.018 Nm. The minimum work required to rotate it from its stable to unstable equilibrium position is :

A bar magnet having a magnetic moment of 2.0 $\times$ 10⁵ JT^$-$1, is placed along the direction of uniform magnetic field of magnitude B = 14 $\times$ 10^$-$5 T. The work done in rotating the magnet slowly through 60$^\circ$ from the direction of field is :

A bar magnet with a magnetic moment $5.0 \mathrm{Am}^{2}$ is placed in parallel position relative to a magnetic field of $0.4 \mathrm{~T}$. The amount of required work done in turning the magnet from parallel to antiparallel position relative to the field direction is _____________.

A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will

The magnetic moment of a bar magnet is $0.5 \mathrm{~Am}^2$. It is suspended in a uniform magnetic field of $8 \times 10^{-2} \mathrm{~T}$. The work done in rotating it from its most stable to most unstable position is:

A thin rectangular magnet suspended freely has a period of oscillation equal to $T.$ Now it is broken into two equal halves (each having half of the original length) and one piece is made to oscillate freely in the same field. If its period of oscillation is $T',$ the ratio ${{T'} \over T}$ is

A fighter plane of length 20 m, wing span (distance from tip of one wing to the tip of the other wing) of 15 m and height 5 m is flying towards east over Delhi. Its speed is 240 ms^−1. The earth’s magnetic field over Delhi is 5 $\times$10^−5 T with the declination angle ~ 0^o and dip of $\theta$ such that sin $\theta$ = 2/3 . If the voltage developed is V_B between the lower and upper side of the plane and V_W between the tips of the wings then V_B and V_W are close to :