Page 153 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

the basis of attraction of the second pin to the first? Write it
down on the basis of the attraction – repulsion law. How many
pins can you hang like this? Try it out.
Why do you think you can hang more pins in this manner? Write
down your inference in the science diary. How will the magnetic
polarity of each pin be? Find it out analysing Fig.11.11 (a)
and present it.
Hold the topmost pin and carefully take away the magnet. What
do you observe? Why did some pins fall down? Discuss.

Examine how many pins could be kept attracted to each other
by holding a pin without touching the magnet, as shown in
Fig. 11.11(b)? What may be the reason for this?
What change occurs in the arrangement of the pins when the
(a)
magnet is removed? Why did the pins fall down? Write it
down.

The phenomenon of a magnetic substance acquiring magnetism
due to the presence of a magnet is Magnetic Induction. The
magnetic force acquired by the magnetic substance is the Induced
Magnetism.
N
Let's see how magnetic poles are developed in a magnetic
substance due to magnetic induction.
You might have understood that the pins attached to the poles
of a magnet change into magnets. Identify the pole at the tip of
the pin touching the north pole of the magnet. Examine by
bringing a magnetic needle near the free end of the pin as in
Fig. 11.12 (a). Write down the polarity of the free end. Hold
(b)

Fig. 11.11

S S S

N N N

(a) (b) (c)
Fig. 11.12

152 Basic Science VIII