Question

The value of earth’s magnetic field can be

A) 0.5G
B) 5G
C) 10G
D) 50G

Answer 1

Hint:Magnetism is the force exerted by magnets when they attract or repel each other. The motion of electric changes causes magnetism. The unit for measuring the magnetic field is Tesla or Gauss. 1 Tesla = 1000 Gauss. Earth's magnetism is supposed to be caused due the flow of electric currents through its core.

Complete step by step answer:
Earth’s magnetic field is equivalent to the magnetic field of a bar magnet which is inclined to the earth’s axis of rotation (A-O-R) at an angle of 11.5^o. The following figure illustrates the above statement.

As the above figure shows that there is a difference between earth’s geographic poles and magnetic poles because of the nature of the magnetic field which is similar to the magnetic field of a bar magnet which is inclined. Now the value of the magnetic field of the earth varies from 25 to 65 microteslas or 0.25 G to 0.65 G. Hence, from the given options 0.5 G is the only value that fits in the possible range of 0.25 G to 0.65 G.

Hence, option answer A is the right choice.

Note: Following points regarding magnetic field must be remembered:
-The direction of the magnetic field of the earth is from the magnetic north pole towards the magnetic south pole of the earth.
-The inclined bar magnet is not a real magnet, it is just a hypothetical magnet.
-There are two types of magnetic fields B-field and the H-field.
-B-field is measured in tesla (T).
-H-field is measured in amperes per metre (A/m).