Advertisements
Advertisements
Question
State briefly the molecular theory of magnetism.
Advertisements
Solution
- Each molecule of a magnetic substance, whether it is magnetized or unmagnetized, is an independent magnet.
- In a magnetized substance, the molecules are arranged in an order so as to produce an external effect. In this order, all the north poles of the molecules of the magnetized substances point to one direction and all their south poles point to a direction opposite to that to which their north poles points.
- In an unmagnetized substance, the molecules are not arranged in any order, so they neutralize the magnetic forces of each other.
- The molecular theory of magnetism was a considerable step forward but later there came an electrical explanation for the magnetism of atoms.
Atoms consist of negatively charged particles (electrons) that revolve around the positively charged nucleus. Electrical current loops are formed in an atom due to the circulation of these electrons. Each current loop behaves a magnetic dipole and hence produce a magnetic field. Also, electrons are also spinning like tops and this adds further magnetism to the atom.
RELATED QUESTIONS
Explain why, two magnetic field lines of not intersect each other.
An electron beam enters a magnetic field at right angles to it as shown in the Figure.
The direction of force acting on the electron beam will be:
to the left
to the right
into the page
out of the page
A magnetic field exerts no force on:
an electrical charge moving perpendicular to its direction
an unmagnetised iron bar
a stationary electric charge
a magnet
Explain what you understand by magnetic induction. What role does it play in attraction of a piece of iron by a magnet?
Figure. shows a bar magnet placed on the table top with its north pole pointing towards south. The arrow shows the north-south direction. There are no other magnets or magnetic materials nearby.
Insert two magnetic field lines on either side of the magnet using arrow head to show the direction of each field line.
Figure. shows a bar magnet placed on the table top with its north pole pointing towards south. The arrow shows the north-south direction. There are no other magnets or magnetic materials nearby.
Indicate by crosses, the likely positions of the neutral points.
Define the Isogonic line.
The magnetic field lines always begin from ____________.
Magnetic lines of force never ______ each other.
Assertion (A): Magnetic field lines never intersect each other.
Reason (R): If they intersect, then at the point of intersection, the compass needle would point towards two directions, which is not possible.
