Answer the following questions:The earth may have even reversed the direction of Its field several times during its history of 4 to 5 billion years. How can geologists know about the earth’s field in such distant past?

Answer the following questions: The earth’s magnetic field varies from point to point in space. Does it also change with time? If so, on what time scale does it change appreciably?

Answer the following questions regarding earth’s magnetism:A vector needs three quantities for Its specification. Name the three Independent quantities conventionally used to specify the earth’s magnetic field.

Answer the following questions regarding earth’s magnetism:Geologists claim that besides the main magnetic N-S poles, there are several local poles on the earth’s surface oriented In different directions. How Is such a thing possible at all?

Answer the following questions:The earth’s field departs from its dipole shape substantially at large distances (greater than about 30,000 km). What agencies may be responsible for this distortion?

Answer the following questions regarding earth’s magnetism:The earth’s field, It Is claimed, roughly approximates the field due to a dipole of magnetic moment 8 xx 10^22 J "T1 located at Its centre. Check the order of magnitude of this number In some way.

Answer the following questions:An electron travelling west to east enters a chamber having a uniform electrostatic field in north to south direction. Specify the direction in which a uniform magnetic field should be set up to prevent the electron from deflecting from its straight line path.

A short bar magnet of magnetic movement 5.25 xx 10^-2 J T^1 is placed with its axis perpendicular to the earth’s field direction. At what distance from the centre of the magnet, the resultant field is inclined at 45^@ with earth’s field on its axis. Magnitude of the earth’s field at the place is given to be 0.42 G. Ignore the length of the magnet in comparison to the distances involved.

A short bar magnet of magnetic movement 5.25 xx 10^-2 J T^-1 is placed with its axis perpendicular to the earth’s field direction. At what distance from the centre of the magnet, the resultant field is inclinedat 45^@ with earth’s field on its normal bisector. Magnitude of the earth’s field at the place is given to be 0.42 G. Ignore the length of the magnet in comparison to the distances involved.

The principle of 'parallax' is used in the determination of distance of nearby stars. The role of distant object O there is now taken by nearby distant stars. The baseline AB is the line joining the Earth's two locations six months apart in its orbit around the Sun. That is the baseline is about the disameter of the earth's orbit = 3 xx 10^11 m. However, even the nearest stars are so distant that with such a long baseline theyshow parallax only of the order 1 s of arc or so. A parsec is a convenient unit of length on the astronomical sxale. It is the distance of an object that will show a parallar of 1s of arc from opposite ends of a baseline equal to the distance from the Earth to the Sum How much is a parsec in terms of metre?