Magnetism and M...

A cylinder of iron is placed so that it is free to rotate around its axis. Initially the cylinder is at rest, and a magnetic field is applied to the cylinder so that it is magnetized in a direction parallel to its axis. If the direction of the external field is suddenly reversed, the direction of magnetization will also reverse and the cylinder will begin rotating around its axis because

A short bar magnet placed with its axis at 30 degree with a uniform external magnetic field of 0.25 T experiences a torque of magnitude equal to 4.5 × 10⁻² J. What is the magnitude of magnetic moment of the magnet?

A closely wound solenoid of 800 turns and area of cross section 2.5 × 10⁻⁴m² carries a current of 3.0 A. What is its associated magnetic moment?

A closely wound solenoid of 800 turns and area of cross section 2.5 × 10⁻⁴m² carries a current of 3.0 A.It is free to turn about the vertical direction and a uniform horizontal magnetic field of 0.25 T is applied.Magnitude of torque on the solenoid when its axis makes an angle of 30° with the direction of applied field

A bar magnet of magnetic moment 1.5 J/T lies perpendicular to the direction of a uniform magnetic field of 0.22 T. What is the torque acting on it?

A bar magnet of magnetic moment 1.5 J/T lies parallel to the direction of a uniform magnetic field of 0.22 T. What is the torque acting on it?

A closely wound solenoid of 2000 turns and area of cross-section 1.6 × 10⁻⁴m², carrying a current of 4.0 A, is suspended through its centre allowing it to turn in a horizontal plane. What is the magnetic moment associated with the solenoid?

A closely wound solenoid of 2000 turns and area of cross-section 1.6 × 10⁻⁴m² , carrying a current of 4.0 A, is suspended through its centre allowing it to turn in a horizontal plane. If a uniform horizontal magnetic field of 7.5 × 10⁻² T is set up at an angle of 3030 with the axis of the solenoid,force and torque on the solenoid are

How will  the force between the two poles change if the two poles are connected by an iron rod keeping the distance between two magnetic poles constant ?

Lenz's law is a consequence of the law of conservation of 

A bar magnet for dipole moment $$10^4\ JT^{-1}$$ is free to rotate around a horizontal plane. A horizontal magnetic field $$4\times 10^{-5}\ T$$ exists on the space. Find the work done in rotating the magnet slowly from a direction parallel to the field to a direction $$60^0$$ from the field.

When the current through the electromagnet of a relay reaches a particular value

A current carrying wire in the neighbourhood produces -

A bar magnet has coercivity $$4\times10^3 Am^{-1}$$. It is placed in a solenoid having $$40$$ turns per cm and is $$1.2m$$ long. The current carried by the solenoid to demagnetize  the bar magnet is :

If a bar magnet in magnetic moment $$m$$ is deflected from an angle $$\theta$$ in a uniform magnetic field of induction $$B$$, the work done in reversing the direction is 

What is the direction of magnetic field at the centre of a coil carrying  clockwise current ?

At Curie temperature the ferromagnetic materials get converted into.

A straight wire lying in a horizontal plane carries a current from north to south.  What will be the direction of magnetic field at a point just underneath it?