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Question
State briefly the modern views on magnetism.
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Solution
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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RELATED QUESTIONS
The magnetic field lines produced by a bar magnet:
(a) originate from the south pole and end at its north pole
(b) originate from the north pole and end at its east pole
(c) originate from the north pole and end at its south pole
(d) originate from the south pole and end at its west pole
The magnetic field lines:
(a) intersect at right angles to one another
(b) interest at an angle 45° to each another
(c) do not cross one another
(d) cross at an angle of 60° to one anotherv
Answer the following question.
Draw the pattern of magnetic field lines of
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(ii) a bar magnet.
List two distinguishing features between the two fields.
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Draw diagram showing the arrangement of the lines of force for a single magnet.
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Define magnetic field lines of force.
