Advertisements
Advertisements
प्रश्न
State briefly the modern views on magnetism.
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.
APPEARS IN
संबंधित प्रश्न
Define magnetic field lines. Describe an activity to draw a magnetic field line outside a bar magnet from one pole to another pole.
A strong bar magnet is placed vertically above a horizontal wooden board. The magnetic lines of force will be:
(a) only in horizontal plane around the magnet
(b) only in vertical plane around the magnet
(c) in horizontal as well as in vertical planes around the magnet
(d) in all the planes around the magnet
A charged particle enters at right angles into a uniform magnetic field as shown:
What should be the nature of charge on the particle if it begins to move in a direction pointing vertically our of the page due to its interaction with the magnetic field?
How will you test whether a given rod is made of iron or copper?
[Hint : Iron rod gets magnetised when placed near a bar magnet by magnetic induction, while copper rod does not get magnetised]
Explain the mechanism of attraction of iron nails by a magnet when brought near them.
A battery can supply a charge of 25 × 104 C. If the current is drawn from battery at the rate of 2.5 A, calculate the time in which battery will discharge completely.
Distinguish between
Magnetic properties of iron and steel.
Magnetic field lines determine ______.
The direction of the magnetic lines around a current-carrying conductor can be easily understood using the ______ rule.
