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प्रश्न
State briefly the modern views on magnetism.
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उत्तर
The molecular theory of magnetism was a considerable step forward but later there came an electrical explanation for the magnetism of atoms and this had wider applications. We have already seen that magnets can be made by an electric current. Atoms contain particles of electricity called electrons that move in orbits about a central nucleus. These electrons behave like an electric current in a single turn of wire and so create a magnetic field. More importantly, the electrons are also spinning like tops and this adds further magnetism to the atom.
The apparently non-magnetic substances are classified as either diamagnetic or paramagnetic respectively. We shall explain these terms very briefly before going on to deal with the strongly magnetic or ferromagnetic substances.
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संबंधित प्रश्न
In the straight wire A, current is flowing in the vertically downwards direction whereas in wire B the current is flowing in the vertically upward direction. What is the direction of magnetic field:
(a) in wire A?
(b) in wire B?
Name the rule which you have used to get the 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.
The intensity of a magnetic field is indicated by the lines of ______.
Select the correct option:
Nickel is a:
How do you account for the following fact?
Soft iron keepers help to prevent the magnets from losing their magnetic properties.
Complete the following diagram of magnets to show the lines of force.
Write the properties of magnetic lines of force.
______ is the number of magnetic field lines passing through a given area.
