Science STD 6 Chapter 10: Fun with Magnets - Exercises

Science STD 6 Chapter 10: Fun with Magnets - Exercises

1. Fill in the blanks in the following:

  1. Artificial magnets are made in different shapes such as ............., ............. and .............

    bar magnet, horse-shoe magnet, cylindrical magnet

  2. The Materials which are attracted towards a magnet are called .............

    magnetic materials

  3. Paper is not a ............. material.

    magnetic

  4. In olden days, sailors used to find direction by suspending a piece of .............

    magnet

  5. A magnet always has ............. poles.

    two

2. State whether the following statements are true or false:

  1. A cylindrical magnet has only one pole.

    False.

  2. Artificial magnets were discovered in Greece.

    False.

  3. Similar poles of a magnet repel each other.

    True.

  4. Maximum iron filings stick in the middle of a bar magnet when it is brought near them.

    False.

  5. Bar magnets always point towards North-South direction.

    True.

  6. A compass can be used to find East-West direction at any place.

    True.

  7. Rubber is a magnetic material.

    False.

3. 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.

The blade used to sharpen the pencil is made of iron or steel, which are magnetic materials. This is the part that is attracted to the magnet, even though the body of the sharpener is made of plastic.

4. 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.

Column I Column II
N - N Repulsion
N - S Attraction
S - S Repulsion
S - N Attraction

5. Write any two properties of a magnet.

Two properties of a magnet are:

  1. A magnet attracts magnetic materials like iron, nickel, and cobalt.
  2. When freely suspended, a magnet always aligns itself in the North-South direction.

6. Where are poles of a bar magnet located?

The poles of a bar magnet are located near its two ends. This is where the magnetic force is the strongest.

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

To find the north pole of an unmarked bar magnet, you can suspend it freely from a thread tied around its center. The magnet will come to rest pointing in the North-South direction. The end of the magnet that points towards the geographic North is its North pole.

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

To magnetize an iron strip, take a strong bar magnet. Place one pole of the magnet near one end of the iron strip. Without lifting the magnet, rub it along the entire length of the strip towards the other end. Lift the magnet and repeat the process about 30-40 times, always starting from the same end and moving in the same direction.

9. How is a compass used to find directions?

A compass is used to find directions by using its magnetized needle, which is pivoted to rotate freely. The needle always comes to rest pointing in the North-South direction. By aligning the compass dial with the North-South poles of the needle, one can determine all other directions like East and West.

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

Column I Column II
Boat gets attracted towards the magnet. The boat is made of a magnetic material.
Boat is not affected by the magnet. The boat is made of a non-magnetic material.
Boat moves towards the North pole of the magnet. A small magnet is fixed along its length with its South pole towards the head of the boat.
Boat moves away from the North pole of the magnet. A small magnet is fixed along its length with its North pole towards the head of the boat.
Boat floats without hanging in a certain direction. The boat has a large magnet fixed along its length.

Suggested Activities

1. Using a compass, find the direction in which windows and entrance to your house or classroom open.

Outline: This activity is a practical application of using a compass. Students learn to determine directions by finding the North-South line and then identifying where their windows or doors are located relative to it. It reinforces the concept of cardinal directions and the function of a compass.

2. Try to place two equal sized bar magnets one above the other such that their north poles are on the same side. Note what happens and write your observations in your note book.

Outline: This activity demonstrates the principle of magnetic repulsion. When two magnets are placed with their North poles facing each other, they will repel one another. The student will observe a force pushing the magnets apart, confirming that like poles repel.

3. 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?

Outline: This activity provides a practical solution to a real-world problem. Since iron nails and screws are magnetic, a magnet can be used to separate them from non-magnetic wooden shavings. By passing a magnet over the mixture, the nails and screws will be attracted and can be easily collected, saving time and effort.

4. You can make an intelligent doll, which picks up the things it likes...

Outline: This is a creative and playful activity to demonstrate magnetism. By secretly placing a magnet inside a doll's hand, students can show how the doll "magically" picks up magnetic objects like iron nails. This helps to visualize the invisible force of magnetism and introduces the difference between magnetic and non-magnetic materials.