Physics Times – July 2019

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22. Magnetism & Matter


23. Magnet
    An object that attracts iron, cobalt, nickel and some
    other materials.


24. Types Of Magnet
    (1) Natural magnets:
    The magnet which is found in nature is called a
    natural magnet.

Eg: Magnetite Fe O2 3.

(II) Artificial magnets:

The magnets which are artificially prepared

are known as artificial magnets.

Eg: These are generally made of iron, steel

and nickel.

3. Magnetic Length
   The shortest distance joining the poles of the

magnet is known as ‘magnetic length’. It is

denoted by 2 l(some time with l).

 The magnetic length is 5 / 6 times the geometric

length of a bar magnet.

4. Pole Strength(m)
   The ability of a pole to attract or repel another
   pole of a magnet is called pole strength.
    S.I. unit of pole strength is ampere meter or
   weber.
    1 weber =


5. Magnet


6. Types Of Magnet


7. Magnetic Length



4. Pole Strength(m)



  0 Am

Where  0 is permeability of free space

(The ability of a medium to allow magnetic lines

to pass through it is called permeability)

4 107

 o

   weber / AA^ m