CBSE NCERT Class VI Science Lesson 13:Lesson 13: Fun with Magnets.
1. Who
discover magnet?
Ans: A Greek shepherd named Magnes discovered magnets 4,000
years ago in Magnesia, Greece. The name magnetite has been derived from
Magnesia or Magnes.
2. What
is magnet?
Ans: Any material that attract iron object is called magnet. The two ends of a magnet are called
its poles. The poles of a magnet
are named as the North Pole and the South Pole. In order to identify the poles,
the North Pole is usually painted in red colour. All magnets have two poles, and they are
called dipoles. Law of magnets :Unlike
poles attract each other and like poles repel each other.
3. Why
magnet called load stone?
Ans: Magnet in the form of a bar was used to find directions
on the earth, and so it is called as a Lodestone.
4. What
are magnetic material and Non-Magnetic
Materials?
Ans: Materials that are attracted by a magnet are called
magnetic materials. Objects made of materials such as iron, cobalt and nickel
are magnetic objects. Examples of magnetic materials include iron nail, key,
metal spade, needle and metal door handle.
Materials that are not attracted by magnets are called
non-magnetic materials. Examples of non-magnetic materials include rubber,
coins, feather and leather.
5. What
are different types of magnets?
Ans: Bar magnets :
In these magnets, the poles are located at the ends of the bar.
Cylindrical magnets: In these magnets, the poles are located at the two circular
ends of the cylinder.
Horseshoe magnets : In these magnets, the poles are
located at the two free ends of the 'U' shape.
6. What
is Compass?
Ans: A compass is an instrument that is used to find
the directions. It has a thin magnetic needle supported from a pivot so that it
can rotate freely. The needle is placed over a dial with the directions marked.
The entire assembly is placed inside an airtight box.
7. How
can you make artificial magnets?
Ans: A rectangular iron bar, an iron needle, a blade or an
iron nail can be turned into a magnet by rubbing a bar magnet over like combing
hair to make artificial magnets.
8. How do
you protect magnets
from losing
their magnetic properties?
Ans: Precautions
to protect magnets from losing their magnetic properties are:
(a) Never
drop magnets from heights. (b) Never heat a magnet. (c) Do
not hammer a magnet.
9. Write some use of
magnet?
Ans: debit
cards, credit cards or ATM cards, audio and video cassettes etc
10. What are
magnetic keepers?
Ans: A soft
iron pieces placed across the ends of a pairs of bar magnets to preserve the
magnetism for a long time is called magnetic keepers.
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