CLASS - 6 || SUBJECT - SCIENCE || Chapter 13 || Fun with Magnets ||
Chapter 13
Fun with Magnets
1.
It was observed that a pencil sharpener gets
attracted by both the poles of a magnet although its body is made of plastic.
Name a material that might have been used to make some part of it.
Ans: Iron is used to make some part of sharpener due to
which it is attracted toward magnet..
2.
Write any two properties of a magnet.
Ans: Two properties of magnets are:
(i) A magnet has two poles: North pole and South pole.
(ii) Like poles repel each other and unlike poles attract each other.
3.
Where are poles of a bar magnet
located?
Ans: Poles are located at the ends of bar magnet just before the
ends. These are north and south poles.
4.
A bar magnet has no markings to
indicate its poles. How would you find out near which end is its north pole
located?
Ans: Take
the bar magnet and suspend it freely with the help of a thread, the end that
points towards north pole will be regarded as north end of the magnet. Take a
bar magnet with known/marked poles on it. Let the north pole of the magnet be
brought closer to the suspended magnet at the end that is pointing towards
north, if it shows repulsion than it is confirmed.
5.
You are given iron strip. How will you make it
into a magnet?
Ans: Making a magnet: Take an iron strip and place it on the
table. Now take a bar magnet and place one of its poles near one edge of the
strip of iron. Without lifting it move it along the length of the iron strip
till you reach the other end. Now lift the magnet and bring the pole to the
same point of strip from where yob began. Repeat this process about 30-40
times. Bring some iron fillings near the strip and observe that the strip
attracts the fillings. This indicates that the iron strip becomes magnet.
Remember that the pole of magnet and direction of
its movement should not change.
6.
How is compass used to find direction?
Ans: A compass is a small case of glass. A magnetised needle
is pivoted inside the box. The needle can rotate freely. Compass also has a
dial with directions marked on it. The compass is kept at the place where we
want to know the directions. When the needle comes to rest it indicates
north-south direction. The compass is then rotated until the north and south
marked on the dial are at the two ends of the needle. Usually different colours
are used to point the ends of needle to identify the north and the south poles.
7.
Write main properties of a magnet.
Ans: (i) Magnet has two poles—south pole and north pole.
(ii) Poles of magnet cannot be isolated.
(iii) Like poles repel each other and unlike poles attract each other.
(iv) Freely suspended magnet aligns in N-S direction.
8.
Write two methods by which a magnet
can be demagnetised.
Ans: (1) By hammering the magnet strongly.
(2) By heating a magnet strongly and keeping it in the east-west direction.
9.
Show that a magnet has two poles. What are the
properties of the poles of a magnet?
Ans. We know that pole is the point where the strength of
the magnet is maximum. So more and more iron particles will be attracted at
poles of a magnet when we bring a magnet near the iron particles. We will
observe the crowdness of particles at the ends of magnet. This indicates the
presence of two poles in a magnet. Hence poles are present in a magnet in pair.
If a magnet is divided into two parts, each part also possesses a pair of poles.
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