Question

State true or false- magnetic lines of force are closed continuous curves.

Answer 1

- Hint: There doesn’t exist a monopole in nature. Wherever you go, you will be seeing magnetic dipoles. Magnetic dipole moment is a vector quantity and it is used to characterize magnetic properties of some matter. Examples like electrons around atomic nuclei, electrons spinning on their axis etc. are all magnetic dipoles in subatomic dimensions.

Complete step-by-step solution

Magnetic lines of force are the imaginary lines that describe the strength and direction of the force. If you use a compass to find out the magnetic lines, they will point in such a way that the lines originating from the north pole are moving away from it and towards the south pole. It describes the influence of magnetic force in a region. The lines of force always originate from the north pole and get into the south pole. Usually, the field lines cannot be calculated at all the places, so, we use field density to indicate the field strength and the number of lines present. In nature, monopoles don't exist. There exist a couple of poles together as one emits the lines of force and one attracts. Monopoles do exist theoretically but they are not practically available. The interesting thing about these magnetic lines of force is that they never come across each other and they always start at the north pole and terminate at the south pole.
This is the reason why they always form closed loops.

Additional information:
We can also find out the strength of the magnetic pole, and it is named as magnetic dipole moment. In a uniform magnetic field, magnitude of dipole moment is directly proportional to the maximum torque on the dipole. The direction of the dipole moment is always perpendicularly away from the side of the surface enclosed by the flow. It is thus a vector by nature.

Note: The abovementioned monopoles only exist theoretically. All the poles in nature exist in a couple and therefore are always closed in nature. The field lines always originate in the north pole and they terminate or enter into the south pole.