Vibration magnetometer work on the principle of [ MPPMT 199]

A magnetic needle suspended by a silk-thread is vibrating in the earth's magnetic field. If the temperature of the needle is increased by 500°C, then [ MNR 1995]

A bar magnet is placed North-south with its North pole due North. The point of zero magnetic field will be in which direction from the centre of the magnet? [ PMT 1995]

A bar magnet of magnetic moment M is kept in uniform magnetic field of strength b making angle θ with its direction. The torque acting on it is [ MPPMT 1998]

If a piece of metal was through to be magnet, which one of the following observations would offer conclusive evidence? [ CET 1994]

The magnetic lines of force inside a bar magnet [ AIEEE 2003]

A tangent galvanometer shows no deflection when current is passed through it. But when the current is reversed, it gives deflection of 180°, then the plane of the coil is

The length of a magnet is larger 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 placed on each other with their like poles together. the time period of this combination will be [ AIEEE 2004]

The material suitable for making electromagnets should have [ AIEEE 2004]

A magnetic needle is kept in a non-uniform magnetic field it experiences [ AIEEE 2005]

Needles N1, N2 and N3 are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will [ AIEEE 2006]

Relative permitivity and permeability of material εr and µr respectively. Which of the following values of these quantities are allowed for a diamagnetic material? [ AIEEE 2008]

Two bar magnets of the same mass, same length and breadth but having magnetic moments M and 2M are joined togather pole to pole and suspended by a string. The time period of assembly in a magnetic field of strength H is 3 seconds. If now the polarity of one of the magnets is reversed and the combination is again made to oscillate in the same field, the time oscillation is :

The earth's magnetic field may be considered to be due to a short magnet placed at the centre of the earth and oriented along the magnetic south-north direction. the ratio of the magnitude of the magnetic field on the earth's surface of magnetic equator to that at the magnetic poles is

The radius of curvature of the path of a charged particle in a uniform magnetic field is directly proportional to [ MNR 1995]

The angle of dip at a place is 60°. A magnetic needle oscillates in a horizontal plane at this place with period T. The same needle will oscillate in a vertical plane coinciding with the magnetic meridian with a period

A dip needle lies initially in the magnetic meridian when it shows an angle of dip θ at a place. The dip circle is rotated through an angle x in the horizontal plane and then it shows an angle of dip θ'. Then ( tanθ' / tanθ) is

Which of the following is diamagnetic

A magnetic needle is kept in a uniform magnetic field. It experiences

Soft iron is used to manufacture electromagnets because their

The magnetic field of short magnet at a distance of 1 m on the axial line is 1 oersted. At a distance of 2m on the same axis, the intensity in oersted is

Two magnets are held together in a stirp up and allowed to oscillate in the earth's field when their like poles are pointing in the same direction, they make 12 vibrations per minute. When unlike poles are pointing in the same direction, they make 4 vibrations per minute. Then the ratio of their magnetic moments are

A small compass needle is placed at the centre of the circular coil in a tangent galvanometer. This is done to ensure that

What happens to the force between two magnetic poles when their pole strengths and distance between them are both doubled

A uniform magnetic needle is suspended from its centre by a thread. Its upper end is now loaded with a mass of 50 mg when the needle becomes horizontal. If the strength of each pole is 98.1 ab-amp × cm and g is 981 cm/sec2, then the vertical componenet of the earth's magnetic induction is

The magnetic field due to a short magnetic dipole of magnetic moment M at a point on the axis of the dipole and at a distance d from it is given by

A magnetic needle vibrates in a vertical plane parallel to the magnetic meridian, about a horizontal axis passing through its centre. Its frequency is n. If the plane of oscillation is turned about a vertical axis by 90°, the frequency of its oscillation in vertical plane will be

If a bar magnetic moment 80 units be cut into two halves of equal lengths, the magnetic moment of the each half will be

A magnet 20cms long with its poles concentrated at its ends, is placed vertically with its ends, is placed vertically with its north pole on the table. At a point due to 20cms south of the pole, a neutral point is obtained. IF H horizontal component of earths magnetic field H=0.3 gauss, then the pole strength of the magnet is approximately

The magnet can be completely demagnetized by [ CET 1994]