Electric Field

Correct answer: They are two dimensional

Explanation:
Let’s analyze each statement about magnetic field lines:

1. They are imaginary lines – True
Magnetic field lines are used to represent the direction and strength of magnetic fields; they are not physically real.

2. They are two dimensional – False
Magnetic field lines exist in three dimensions. They form closed loops from the north to the south pole outside a magnet and continue through the magnet from south to north.

3. They are closed loops – True
Unlike electric field lines, magnetic field lines always form closed continuous loops.

4. They never intersect with each other – True
If two magnetic field lines were to intersect, it would imply two directions of the magnetic field at a single point, which is not possible.

Hence, the false statement is: They are two dimensional.

Correct answer: north-south directions

Explanation:
A compass needle is a small magnet, and when it is freely suspended, it aligns itself with the Earth's magnetic field.

The Earth acts like a giant magnet with its magnetic south near the geographic North Pole and magnetic north near the geographic South Pole.

Thus, the compass needle aligns itself along the geographic north-south direction, with the north pole of the needle pointing towards the geographic north.

Hence, the correct answer is: north-south directions.

The Tesla (T) is the SI unit of magnetic flux density (or magnetic field strength).

It is defined as: $ $

So the correct answer is (3).