1. Fill in the blanks in the following:
(i) Artificial magnets are made in different shapes such as bar, horseshoe, and cylindrical.
(ii) The Materials which are attracted towards a magnet are called magnetic materials.
(iii) Paper is not a magnetic material.
(iv) In olden days, sailors used to find direction by suspending a piece of magnet.
(v) A magnet always has two poles.
2. State whether the following statements are true or false:
(i) A cylindrical magnet has only one pole. False
(ii) Artificial magnets were discovered in Greece. False
(iii) Similar poles of a magnet repel each other. True
(iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them. False
(v) Bar magnets always point towards North-South direction. True
(vi) A compass can be used to find East-West direction at any place. True
(vii) 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.
Answer: Steel or iron (used in the blade of the sharpener).
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. :
N-N Repulsion
N-S Attraction
S-N Attraction
S-S Repulsion
5. Write any two properties of a magnet.
Answer: A magnet always has a north and a south pole. Opposite poles of magnets attract each other, and similar poles repel each other.
6. Where are poles of a bar magnet located?
Answer: The poles of a bar magnet are located at its two ends.
7. A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?
Answer: Suspend the magnet freely so it can rotate. The end that points towards the geographic North is the north pole.
8. You are given an iron strip. How will you make it into a magnet?
Answer:
Step 1: Start with a strong bar magnet to magnetize the iron strip.
Step 2: Use one end of the magnet to rub along the iron strip. Start from one end of the strip and move to the other end. Lift the magnet and return to the starting point. Do this several times.
Step 3: Make sure to always rub in the same direction. This helps to align the iron particles in the strip to create a magnetic field.
Step 4: After rubbing the magnet on the strip a few times, test if the strip has become magnetic by seeing if it can pick up small metal objects like paper clips.
9. How is a compass used to find directions?
Answer: A compass has a magnetized needle that aligns with Earth’s magnetic field. When the compass is held flat, the needle points towards the magnetic North, helping to determine directions.
10. 10. A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. The effect observed in each case is stated in Column I. Possible reasons for the observed effects are mentioned in Column II. Match the statements given in Column I with those in Column II.
1) Boat gets attracted towards the magnet ==> Boat is made up of magnetic material
2) Boat is not affected by the magnet ==> Boat is made up of non-magnetic material
3) Boat moved towards the magnet when the north pole was brought near its head ==> Boat is fitted with a magnet with the south pole towards its head
4) Boat moves away from the magnet when the north pole is brought near its head ==> Boat is fitted with a magnet with a north pole towards its head
5) Boat floats without changing its direction ==> Boat has a small magnet fixed along its length