D. Give reasons for the following statements.
1. The direction of magnetic field lines inside a magnet is from S to N.
2. Magnetic field lines do not intersect.
3. Suspended bar magnet always points, towards north and south directions.
4. Magnetic force is not a contact force.
5. A magnet only attracts iron, cobalt and nickel.
Answers
Explanation:
1) Inside the magnet, the direction of field lines is from its south pole to its north pole. Thus the magnetic field lines are closed curves.
2) Two magnetic field lines do not intersect each other because if there was point of intersection, The compass needle would point towards 2 directions. Which means that the magnetic field has two different directions, which is not possible.
3) A freely suspended magnet always rests in the north-south direction because the magnetic south pole of the earth lies in the geographic north direction and the magnetic north pole of the earth lies in the geographical south direction.
4) Magnetic forces are non contact forces; they pull or push on objects without touching them. Magnets are only attracted to a few 'magnetic' metals and not all matter. Magnets are attracted to and repel other magnets.
5) Ferromagnetism is a phenomenon that occurs in some metals, most notably iron, cobalt and nickel, that causes the metal to become magnetic. The atoms in these metals have an unpaired electron, and when the metal is exposed to a sufficiently strong magnetic field, these electrons' spins line up parallel to each other.
So the field lines travel outwards from one side of the loop, the North pole, round to the other side, the South pole, then go inside the loop to complete their circuit. This has to happen because magnetic field lines cannot begin or end so they always have to form closed loops.
The magnetic field lines never intersect each other because if two or more lines intersect each other than it means that at that point of intersection, the magnetic field has two directions at the same point. This is not possible for a magnetic field to point in more than one direction at the same point.
A freely suspended magnet always rests in the north-south direction because the magnetic south pole of the earth lies in the geographic north direction and the magnetic north pole of the earth lies in the geographical south direction
.Magnetic forces are non contact forces; they pull or push on objects without touching them. Magnets are only attracted to a few 'magnetic' metals and not all matter. Magnets are attracted to and repel other magnets.
Iron, Cobalt, Nickel, Neodymium are ferromagnetic substances. These substances are special in the sense; first of all they have unpaired electrons in the valence orbital which act as magnetic dipoles. These substances with unpaired electrons are called paramagnetic substances.