Fun with Magnets


How is compass used to find direction?


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.



Fun with Magnets

Q 1.

At which place on a magnet, its magnetic force is maximum?

Q 2.

State whether the following statements are true or false:
(i) A cylindrical magnet has only one pole.
(ii) Natural magnets were discovered in Greece.
(iii) Similar poles of a magnet repel each other.
(iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them.
(v) Bar magnets always point towards North-South direction when suspended freely in air.
(vi) A compass can be used to find East-West direction at any place.
(vii) Rubber is a magnetic material.

Q 3.

Where are poles of a bar magnet located?

Q 4.

A given bar magnet was broken into pieces. Where will be its North and South pole?

Q 5.

In which direction does a suspended magnet come to rest?

Q 6.

Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks.

Q 7.

Write two methods by which a magnet can be demagnetised.

Q 8.

How can you separate a magnetic substance from a mixture?

Q 9.

What happens when N-pole of a magnet is brought near the N-pole of a suspended magnet?

Q 10.

Name the shepherd after which magnet was named.

Q 11.

A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?

Q 12.

Show that a magnet has two poles. What are the properties of the poles of a magnet?

Q 13.

It is said that repulsion is a sure test for magnetism. Why is it so?

Q 14.

Draw the diagram of (a) Bar magnet (b) Horse-shoe magnet.

Q 15.

Write any two properties of a magnet.

Q 16.

You are given two rods. Out of these, one is an iron rod and the other one is magnet, how will you identify these rods?

Q 17.

Fill in the blanks in the following:
(i) Artificial magnets are made in different shapes such as_________ ,_______ and
(ii) The materials which are attracted towards a magnet are called_________
(iii) Paper is not a________
(iv) In olden days, sailors used to find direction by suspending a piece of
(v) A magnet always has ________poles.

Q 18.

Write main properties of a magnet.

Q 19.

Identify magnetic and non-magnetic substances from the list given below: Iron, Steel, Nickel, Plastic, Wood, Copper and a Stainless Steel spoon

Q 20.

You are given iron strip. How will you make it into a magnet?

Q 21.

How is compass used to find direction?

Q 22.

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.

Q 23.

Name the compound of iron contained in lode stone.

Q 24.

Draw a diagram of a magnetic compass.

Q 25.

A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. Effect observed in each case is stated in Column I. Possible reason for the observed effects are mentioned in Column II. Match the statements given in Column I with those in Column II.  

Q 26.

Few iron nails and screws got mixed with the wooden shavings while a carpenter was working with them.How can you help him in getting the nails and screws back from the scrap without wasting his time in searching with his hands?

Q 27.

It is advised to keep the magnets away from television, mobiles, CD and computers  Explain why?