Magnetism

What happens when opposite magnetic poles are brought close together?

• They repel each other

• They attract each other

• They have no effect

• They oscillate

Answer explanation

When opposite magnetic poles are brought close together, they attract each other. This is because opposite poles have different magnetic orientations, causing them to pull towards each other. The magnetic force between them overcomes any repulsive forces, resulting in attraction. This phenomenon is a fundamental property of magnets and is used in various applications, such as magnetic attraction in electric motors and the functioning of magnetic compasses.

Which of the following is an example of a permanent magnet?

• A refrigerator magnet

• An electromagnet

• Copper Bar

Answer explanation

A refrigerator magnet is an example of a permanent magnet. It is a magnet that sticks to metal objects and can hold them in place. Unlike an electromagnet, which requires an electric current to generate a magnetic field, a refrigerator magnet has a permanent magnetic field. The copper bar is not a permanent magnet. It is a conductor of electricity but does not have a magnetic field. Therefore, the correct choice is a refrigerator magnet.

In a magnetic field, magnetic field lines run…...

• South to North

• East to West

• West to East

• North to South

Answer explanation

The question asks about the direction of magnetic field lines in a magnetic field. The correct answer is 'North to South'. In a magnetic field, the magnetic field lines always run from the North pole to the South pole. This direction is consistent with the behavior of magnetic fields. It is important to understand the concept of magnetic field lines and their direction in order to comprehend the behavior of magnetic fields.

Which of the following is NOT a magnetic material?

• Aluminum

• Iron

• Nickel

• Cobalt

Answer explanation

The question asks which material is NOT magnetic. Out of the given options, Aluminum is the correct answer. Aluminum is a non-magnetic material, unlike Iron, Nickel, and Cobalt, which are all magnetic. Therefore, Aluminum does not exhibit magnetic properties.

What happens when like magnetic poles are brought close together?

• They repel each other

• They attract each other

• They have no effect

• They oscillate

Answer explanation

When like magnetic poles are brought close together, they repel each other. This is because like poles have the same magnetic polarity, causing a force of repulsion between them. This phenomenon is a result of the magnetic field lines interacting and pushing against each other. The repulsion between like magnetic poles is a fundamental property of magnetism.

What is a compass' north end attracted to?

• The south end of a magnet

• The north end of a magnet

Answer explanation

A compass' north end is attracted to the south end of a magnet, so the correct answer is 'The south end of a magnet'.

Which of the following is NOT a magnetic pole?

• South pole
• North pole
• Monopole

In a bar magnet, where is the magnetic field the strongest?

• At the poles

• Where the field lines are furthest apart

• In the middle

• It's uniform throughout

Answer explanation

The magnetic field in a bar magnet is strongest at the poles. This is because the magnetic field lines are concentrated and closer together at the poles, indicating a higher magnetic field strength. In contrast, the field lines are furthest apart in the middle of the magnet, where the magnetic field is weaker. The magnetic field is not uniform throughout the magnet. Therefore, the correct choice is 'At the poles'.

What do you call a material that can be easily magnetized and retains its magnetism for a long time?

• Magnetic insulator

• Permanent magnet

• Magnetic conductor

• Magnetic insulator

Answer explanation

A permanent magnet is a material that can be easily magnetized and retains its magnetism for a long time. It is a type of magnet that does not require an external magnetic field to maintain its magnetic properties. This makes it a suitable choice for various applications, such as in electric motors, generators, and magnetic storage devices. The other options, magnetic insulator and magnetic conductor, do not accurately describe a material that retains its magnetism for a long time. Therefore, the correct choice is a permanent magnet.

What type of magnet is created when an electric current flows through a coil of wire?

• Electromagnet

• Permanent magnet

• No magnet is formed

• Magnetic insulator

Answer explanation

When an electric current flows through a coil of wire, it creates an electromagnet. This is because the flow of current generates a magnetic field around the wire, which in turn magnetizes the coil. Unlike a permanent magnet, an electromagnet can be turned on and off by controlling the flow of current. Therefore, the correct choice is Electromagnet.