1.
1. Which of the following is not a property of magnets?
Correct Answer
A. They may not have opposite polarities.
Explanation
Magnets always have opposite polarities, meaning that one end is a north pole and the other end is a south pole. This is a fundamental property of magnets and is necessary for their attraction and repulsion. Therefore, the statement "They may not have opposite polarities" is not a property of magnets and is incorrect.
2.
2. What would happen when two like poles of magnets are brought near to each other?
Correct Answer
A. Repulsion
Explanation
When two like poles of magnets are brought near to each other, they will experience repulsion. This is because like poles of magnets have the same magnetic polarity, which causes them to repel each other. This repulsive force is a fundamental property of magnets and is a result of the alignment of magnetic domains within the magnets.
3.
3. The diagram below shows a few nails attracted to one another.
What is the name of the process, which enables the nails to attract one another?
Correct Answer
C. Induction
Explanation
The process that enables the nails to attract one another is called induction. Induction occurs when an object becomes electrically charged without direct contact with a charged object. In this case, the nails are attracting each other due to the presence of an electric charge induced in them.
4.
4. Which of the following materials is most suitable to be made into a permanent
magnet?
Correct Answer
B. Steel
Explanation
Steel is the most suitable material to be made into a permanent magnet because it has a high magnetic permeability, which allows it to retain its magnetism for a longer period of time. Steel also has a high coercivity, meaning it requires a large amount of magnetic force to demagnetize it. This makes steel an ideal choice for creating magnets that can be used in various applications, such as motors, generators, and magnetic storage devices.
5.
5. Which of the following is not one of the applications of a permanent magnet?
Correct Answer
D. Circuit breaker
Explanation
A permanent magnet is not used in a circuit breaker. Circuit breakers are designed to interrupt the flow of electric current in a circuit when there is an overload or a fault. They typically use electromagnets or solenoids to detect the abnormal current and trip the breaker. Permanent magnets, on the other hand, are commonly used in generators, electric motors, and loudspeakers to create magnetic fields for various purposes.
6.
6. A small plotting compass is placed near a bar magnet as shown.
Which of he following correctly shows the direction of needle of the compass?
Correct Answer
D. D
7.
7. Which of the following methods is the most appropriate to show that a substance is a
magnet?
Correct Answer
B. It can repel another magnet.
Explanation
The most appropriate method to show that a substance is a magnet is if it can repel another magnet. This is because magnets have two poles, a north pole and a south pole, and like poles repel each other. If a substance can repel another magnet, it indicates that it also has magnetic properties and is therefore a magnet itself.
8.
8. Which of the following substance is most suitable to be used as the needle of a
plotting compass?
Correct Answer
B. Steel
Explanation
Steel is the most suitable substance to be used as the needle of a plotting compass because it is a magnetic material. Steel contains iron, which is highly magnetic, making it ideal for creating a compass needle that can align with the Earth's magnetic field. Copper, iron, and aluminium are not as magnetic as steel, so they would not be as effective in accurately pointing towards magnetic north.
9.
9. Which of the following is used to demagnetise a magnet?
Correct Answer
C. Use alternative current
Explanation
Using alternative current is the correct answer because when an alternating current is passed through a magnet, it creates a continuously changing magnetic field. This changing magnetic field disrupts the alignment of the magnetic domains within the magnet, causing it to lose its magnetism or become demagnetized.
10.
10. A bar magnet is covered by a piece of paper. When the plotting compasses are
placed on the top of the paper, the following observations are recorded.
Which of the following correctly shows the arrangement of the magnet?
Correct Answer
D. D
Explanation
Option D correctly shows the arrangement of the magnet. In this arrangement, the plotting compasses are pointing towards the North Pole of the bar magnet. This indicates that the North Pole of the magnet is located towards the top of the paper, while the South Pole is located towards the bottom.