Magnetic Effect...

A needle made of bismuth is suspended freely in a magnetic field. The angle which the needle makes with the magnetic field is

The magnetic susceptibility of a material of a rod is 449. Permeability of vacuum is 4π x 10^-7 henry/metre. The absolute permeability of the material of the rod (in henry/metre) is

A magnet of length 10 cm and magnetic moment 1 Am² is placed along the side AB of an equilateral triangle ABC. If the length of side AB is 10 cm, then the magnetic field at point C is

A magnetic dipole is acted upon by two magnetic fields which are inclined to each other at an angle of 75°. One of the fields has a magnitude of 10^-2 T. The dipole attains stable equilibrium at an angle of 30° with this field. What is the magnitude of the other field?

A steel wire of length 'l' has a magnetic moment M. It is bent into a semicircular arc. The new magnetic moment is

A bar magnet of magnetic moment 2.0 JT^-1 lies aligned with the direction of a uniform magnetic field of 0.25 T. What is the work done to turn the magnet so as to align its magnetic moment opposite to the field direction?

Directions: From the statements of Assertion and Reason mark the correct answer from the options.

(a) If both assertion and reason are true, and reason is the correct explanation of assertion.
(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
(c) If assertion is true, but reason is false.
(d) If both assertion and reason are false.

Assertion: Diamagnetic materials can exhibit magnetism.
Reason: Diamagnetic materials have permanent magnetic dipole moment.

A magnet of magnetic moment M and length 2l is bent at its mid-point such that the angle of bending is 60°. Now, the magnetic moment is

Directions: In the following question, a statement of Assertion is given, followed by a corresponding statement of Reason. Of the statements, mark the correct answer as:

(a) If both assertion and reason are true and the reason is the correct explanation of assertion.
(b) If both assertion and reason are true but the reason is not the correct explanation of the assertion.
(c) If assertion is true but reason is false.
(d) If both assertion and reason are false.

Assertion: The true geographic north direction is found by using a compass needle.
Reason: The magnetic meridian of the earth is along the axis of its rotation.

Two identical thin bar magnets are placed mutually at right angles, such that the north pole of one touches the south pole of the other. The length and the pole strength of each bar are L and m, respectively. The resultant magnetic moment of the system is

A circular coil of 20 turns and radius 20 cm is mounted vertically with its plane in magnetic meridian. A small magnetic needle is placed at the centre of the coil. When a current is passed through the coil, the needle is deflected through 45^o . If the horizontal component of Earth's field is 0.34 x 10^-4 T, the current in the coil is:

Which of the following quantities is/are used to determine the strength of Earth`s magnetic field at a point on Earth's surface?

(I) Magnetic declination
(II) Dip

When a material is subjected to a small magnetic field H, the intensity of magnetisation is proportional to

A bar magnet used in a vibration magnetometer is heated, so as to reduce its magnetic moment by 36%. The time period of the magnet (neglecting the changes in the dimension of the magnet) :

Directions: The following question has four choices out of which only one is correct.

A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm, respectively, on the opposite sides.



Ratio of the magnitudes of the magnetic fields at these points will be

A magnet makes 30 oscillations/min in Earth's magnetic field. If the magnetic field is doubled, the period of oscillation of magnet is

A paramagnetic substance of susceptibility 3 x 10^-4 is placed in a magnetic field of 4 x 10^-4 Am^-1. What is the intensity (in Am^-1) of magnetisation?

A bar magnet is oscillating in Earth's magnetic field with a period T. What happens to its period and motion if its mass is quadrupled?

Two short bar magnets of magnetic moment 'M' each are arranged at the opposite corners of a square of side 'd', such that their centres coincide with the corners and their axes are parallel. If the like poles are in the same direction, then the magnetic field at any of the other corners of the square is

The effective length of a magnet is 31.4 cm and its pole strength is 0.5 A-m. What will be the magnetic moment if it is bent in the form of a semicircle?

The force between two magnetic poles is F. If the distance between the poles and pole strength of each pole are doubled, then the force experienced is

Which of the following has the highest magnetic permeability?

A toroidal solenoid has 3000 turns and a mean radius of 10 cm. It has a soft iron core of relative permeability 2000. What is the magnitude of the magnetic field in the core, when a current of 1 A is passed through the solenoid?

A magnetic needle, suspended by a highly flexible and highly temperature-resistant thread, is vibrating in Earth's magnetic field. If the temperature of the needle is increased by 500°C, then

For a paramagnetic material, the dependence of magnetic susceptibility X on absolute temperature T is given by (C is a constant)