Case: Read the passage and answer the following passage

The causes of the earth to have a magnetic field are not clear. Originally the magnetic field was thought of as arising from a giant bar magnet placed approximately along the axis of rotation of the earth and deep in the interior. However, this simplistic picture is certainly not correct. The magnetic field is now thought to arise due to electrical currents produced by convective motion of metallic fluids (consisting mostly of molten iron and nickel) in the outer core of the earth. This is known as the dynamo effect. The magnetic field lines of the earth resemble that of a (hypothetical) magnetic dipole located at the centre of the earth. The axis of the dipole does not coincide with the axis of rotation of the earth but is presently titled by approximately 11.3° with respect to the later. In this way of looking at it, the magnetic poles are located where the magnetic field lines due to the dipole enter or leave the earth. The location of the north magnetic pole is at latitude of 79.74° N and a longitude of 71.8° W, a place somewhere in north Canada. The magnetic South Pole is at 79.74° S, 108.22° E in the Antarctica. The pole near the geographic north pole of the earth is called the north magnetic pole. Likewise, the pole near the geographic South Pole is called the south magnetic pole. There is some confusion in the nomenclature of the poles. If one looks at the magnetic field lines of the earth, one sees that unlike in the case of a bar magnet, the field lines go into the earth at the north magnetic pole (Nm ) and come out from the south magnetic pole (Sm ). The convention arose because the magnetic north was the direction to which the north pole of a magnetic needle pointed; the north pole of a magnet was so named as it was the north seeking pole. Thus, in reality, the north magnetic pole behaves like the south pole of a bar magnet inside the earth and vice versa.

In a bar magnet, magnetic field lines:

Form closed continuous curves, directed from north to south outside the magnet and from south to north inside the magnet

The correct answer is Option 2: Form closed continuous curves, directed from north to south outside the magnet and from south to north inside the magnet

Option 1 : “Originate from the north pole and terminate at the south pole”. This is incorrect. This statement is only partially correct. It describes the direction of magnetic field lines outside the magnet, but ignores the fact that inside the magnet the lines continue from south to north, forming complete closed loops. Hence, field lines do not actually originate or terminate at the poles.

Option 2 : “Form closed continuous curves, directed from north to south outside the magnet and from south to north inside the magnet”. This is correct. Magnetic field lines of a bar magnet are always continuous closed loops. Outside the magnet, the field lines emerge from the north pole and enter the south pole, while inside the magnet they return from south to north. Since isolated magnetic poles do not exist, the field lines can never truly begin or end.

Option 3 : “Move from one pole to another only outside the magnet”. This is incorrect because magnetic field lines also exist inside the magnet.

Option 4 : “Emerge radially outward from both poles”. This is incorrect because magnetic field lines do not spread outward identically from both poles. They specifically emerge from the north pole and enter the south pole, following curved paths rather than radial outward lines from both ends.