Chapter 4: Exploring Magnets
Comprehensive Exercise (Made for exam preparation)
Class 6 Science
Question 1: Choose the correct option (Multiple Choice Questions):
1. Which of the following materials is attracted to a magnet?
Answer: (C) Iron.
2. Where is the magnetic strength maximum in a bar magnet?
Answer: (B) Near the ends (poles).
3. What happens when the North pole of one magnet is brought near the North pole of another magnet?
Answer: (B) They repel each other.
4. Which ancient Indian device was used for navigation at sea, which worked like a magnetic compass?
Answer: (A) Matsya-yantra.
5. What does the red-painted end of a magnetic compass needle usually indicate?
Answer: (C) North direction.
Question 2: Fill in the blanks with the appropriate words:
- 1. Materials that stick to a magnet are called magnetic materials.
- 2. A magnetic compass has a needle that can rotate freely and it always rests in the North-South (or North) direction.
- 3. The two ends of a bar magnet where maximum iron filings stick are known as its poles.
- 4. Opposite (unlike) poles of two magnets attract each other.
- 5. Magnetic effect can act through non-magnetic materials like wood, plastic, and glass.
Question 3: State whether the following statements are True or False:
- 1. A plastic ruler and a wooden cork are magnetic materials.
Answer: False (They are non-magnetic). - 2. If we spread iron filings on a paper and place a bar magnet over it, the filings stick uniformly all over the magnet.
Answer: False (They stick mostly near the poles). - 3. Like poles (North-North or South-South) of two magnets repel each other.
Answer: True. - 4. A magnetic compass is a small circular box used to find directions.
Answer: True. - 5. A magnet can move a steel paperclip placed inside a glass bowl of water without getting wet.
Answer: True.
Question 4: Match the items in Column 'A' with the correct items in Column 'B':
| Column 'A' | Column 'B' |
|---|---|
| 1. Magnetic Compass | (a) Attract each other |
| 2. Matsya-yantra | (b) Repel each other |
| 3. Like poles of a magnet | (c) Stick mostly to the poles of a magnet |
| 4. Unlike poles of a magnet | (d) Small device with a dial used to find directions |
| 5. Iron filings | (e) Ancient Indian fish-shaped iron piece in oil for navigation |
Correct Matches:
- 1 → (d) Small device with a dial used to find directions
- 2 → (e) Ancient Indian fish-shaped iron piece in oil for navigation
- 3 → (b) Repel each other
- 4 → (a) Attract each other
- 5 → (c) Stick mostly to the poles of a magnet
Question 5: Classification. Classify the following items into "Magnetic Materials" and "Non-Magnetic Materials":
Items: 1. Iron sewing needle, 2. Wooden cork, 3. Plastic strip, 4. Steel paperclip, 5. Glass bowl.
- Magnetic Materials: 1. Iron sewing needle, 4. Steel paperclip.
- Non-Magnetic Materials: 2. Wooden cork, 3. Plastic strip, 5. Glass bowl.
Question 6: Answer the following questions in one sentence:
1. What happens when you bring a magnet near objects made of iron?
Answer: When a magnet is brought near objects made of iron, the objects stick to the magnet.
2. What is a magnetic compass?
Answer: A magnetic compass is a small circular box with a magnetised needle balanced on a pin that rotates freely to indicate directions.
3. Name the two poles of a magnet.
Answer: The two poles of a magnet are the North pole (N) and the South pole (S).
4. Does a piece of wood placed between a magnet and a compass needle stop the magnetic effect?
Answer: No, the magnetic effect can act through non-magnetic materials like wood, so it does not stop the effect.
5. How do two matchbox cars with magnets act if their like poles (e.g., North and North) face each other?
Answer: The two cars will run away (repel) from each other.
Question 7: Give scientific reasons:
1. Reason: Iron filings stick mostly to the ends of a bar magnet.
Answer: Because the magnetic strength of a bar magnet is maximum near its ends, which are called its poles.
2. Reason: The needle of a magnetic compass is painted red at one end.
Answer: The red-painted end rests in the North direction, which makes it easy for users to quickly identify the North direction and navigate.
3. Reason: A mechanic dropping steel screws uses a magnet to collect them.
Answer: Because steel is a magnetic material, a magnet easily attracts all the scattered screws, making it much faster to pick them up.
4. Reason: We can move steel balls in a maze without touching them using a magnet placed below a cardboard tray.
Answer: Because the magnetic force can pass through non-magnetic materials like a cardboard tray to attract the steel balls.
5. Reason: In the 'hopping frog' toy, the frog hops when the plastic strip is slid over a scale.
Answer: Because the ring magnet attached to the frog repels the ring magnets placed on the scale when their like poles come close to each other.
Question 8: Answer the following questions in short (2-3 sentences):
1. What did ancient Indians use for navigation at sea before the modern magnetic compass?
Answer: Ancient Indians used a device called matsya-yantra. It consisted of a magnetised fish-shaped iron piece kept in a vessel of oil, which pointed in the North-South direction.
2. State the behaviour of magnets when they are brought close to each other.
Answer: When two magnets are brought close to each other, their like poles (North-North or South-South) repel or push each other away. Their unlike poles (North-South) attract or pull each other.
3. How can you find the poles of a bar magnet using iron filings?
Answer: Spread some iron filings on a sheet of paper and place the bar magnet over them. Gently tap the paper; you will observe that maximum iron filings stick near the two ends of the magnet, indicating its poles.
4. Describe how a compass needle behaves when the South pole of a bar magnet is brought near its North pole.
Answer: The compass needle is also a small magnet. When the South pole of a bar magnet is brought near the North pole of the compass needle, they attract each other, and the needle moves closer to the magnet.
5. Prove with an example that magnetic effect can pass through water and glass.
Answer: If we drop a steel paperclip in a glass bowl full of water and move a magnet on the outer surface of the glass, the paperclip moves along with the magnet. This shows magnetic force passes through glass and water.