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प्रश्न
State briefly the molecular theory of magnetism.
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उत्तर
- 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.
संबंधित प्रश्न
Explain why, two magnetic field lines of not intersect each other.
Define magnetic field lines. Describe an activity to draw a magnetic field line outside a bar magnet from one pole to another pole.
Which of the following statements is incorrect regarding magnetic field lines?
(a) The direction of magnetic field at a point is taken to be the direction in which the north pole a magnetic compass needle points.
(b) Magnetic field lines are closed curves.
(c) If magnetic field lines are parallel and equidistant, they represent zero field strength.
(d) Relative strength of magnetic field is shown by the degree of closeness of the field lines.
Copy the figure below which shows a plotting compass and a magnet. Label the N pole of the magnet and draw field line on which the compass lines
Can two magnetic field lines intersect each other? Give reason to your answer.
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.
Complete the following diagram of magnets to show the lines of force.

Complete the following diagram of magnets to show the lines of force.

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.
