Question

If you made a map of magnetic field lines at Melbourne in Australia, then the magnetic field lines seem to be:
(A) go into the ground
(B) come out of the ground
(C) maintain a spiral path on the surface of earth
(D) move on helical path above the surface of ground

Answer 1

Hint: If we make a map of Earth’s magnetic field it will help us to study about the outer core of the earth. And for making the map we used to measure the declination that is the angle between magnetic north and the true north.

Complete step by step solution:
For making the map we need a GPS to know the true north. First of all, have a line of constant longitude. Then put two sticks on the line. And standing between the two sticks we would know about the true north. Again, standing at the same position the compass needle is used to measure the magnetic north. Then the angle between the magnetic north and true north is calculated. Then the declination is calculated.

Trying this in other locations of the earth’s surface the map of magnetic field lines can be found. The magnetic field of the lines are imaginary lines. The imaginary magnetic field lines are never met or cut or intersected with each other.
Melbourne in Australia is in the southern hemisphere of the earth. Therefore, the north pole of earth’s magnetic field lines lies there. Thus, the magnetic field lines seem to come out of the ground.

The answer is option B.

Note: The outer core of the earth is very hot and it became electrically conductive material. Thus, they will create the magnetic field lines. These magnetic field lines will behave differently in every part of Earth. The magnetic field lines travel from north pole to south pole.