Page 155 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

Susceptibility and On the basis of properties you have identified,
Retentivity which is suitable for making strong temporary
magnets? soft iron or steel? Write down which
The ability of magnetic substances magnetic property of steel is used for making
to get magnetised under the permanent magnets.
influence of a magnetic field is
Susceptibility. Retentivity is the
Soft iron Steel
ability to retain the magnetism
thus acquired. $ The ability to retain $ ...............................................
magnetism acquired
(retentivity) is very
low.

$ ............................................... $ Is not easily subjected
to magnetic induction.
In other words, its
susceptibility is very
low.

Table 11.2

Permeability

Place an iron ring or a large iron nut between the poles of two
magnets as shown in Figure 11.14. Place a thin glass plate above
them and sprinkle iron filings on it. Tap gently on the glass plate.
What do you observe? Do the iron filings stick to the hollow part
of the nut?
Compare the pattern you got with the one given in the figure.
What inference do you arrive at?

The ability of soft iron to permit magnetic lines of force pass
through it is greater than that of air. That is, magnetic lines of
force pass more easily through soft iron than through air.

Fig. 11.15

154 Basic Science VIII