The magnetic lines of force inside a bar magnet are:
1. | from the south to the north pole. |
2. | from the north to the south pole. |
3. | not present. |
4. | intersecting each other. |
The material which is used to make permanent magnet has:
1. | High retentivity, low coercivity |
2. | Low retentivity, low coercivity |
3. | Low retentivity, high coercivity |
4. | High retentivity, high coercivity |
On a magnetic map, the lines joining the points of the same value of the horizontal component of the earth's magnetic field are called :
1. Aclinic lines
2. Isoclinic lines
3. Isodynamic lines
4. Isogonic lines
What is the unit of pole strength of a bar magnet?
1. ampere-metre
2. ampere/metre
3. ampere/metre2
4. ampere-metre2
The ratio of magnetic length and geometrical length of a bar magnet is about :
1. 0.84
2. 0.42
3. 0.21
4. 1
An electric cable is carrying current from north to south. The position of the null point from the cable is:
1. Vertically upward
2. Vertically downward
3. Eastward
4. Nowhere
A substance is placed in an external magnetic field. If the direction of induced dipole moment is opposite to the direction of the applied magnetic field, then the substance may be
1. Paramagnetic
2. Diamagnetic
3. Ferromagnetic
4. Both (1) & (3)
If Bo is magnetic flux density in vacuum produced by a magnetising force and magnetic flux density produced by the magnetisation of a material due to the same magnetising force is Bm, then the total magnetic flux density in the material is :
A magnet (primary) oscillates with frequency in earth's magnetic field (BH) alone. Now a secondary magnet is placed near the primary magnet. If B is the magnetic field of the second magnet on the primary magnet in the direction of BH, the primary magnet oscillates with frequency , then the ratio of B/BH is :
1.
2. -1
3. + 1
4. -1
The angle of dip is on a given meridian which is at an angle with the magnetic meridian. If is the angle of dip on another meridian which is perpendicular to the first meridian, then are related as :
1. cot2 = cot2+cot2
2. tan2 = tan2+tan2
3. tan =
4. tan = tan + tan