Test: Magnetism - Primary 5 MCQ

The magnetic field is the region around a magnet where it can exert a force on magnetic materials. This area is invisible but can be demonstrated using iron filings or magnetic compasses.

Sir William Gilbert is recognized as the "Father of Electricity and Magnetism" for his groundbreaking work in the late 16th century, including the idea that the Earth itself acts as a giant magnet and his studies on magnetic forces.

A soft iron strip placed across the ends of bar magnets during storage helps maintain the magnetic properties of the magnets by providing a closed path for the magnetic lines of force, preventing rapid loss of magnetism.

The primary difference is that temporary magnets lose their magnetism quickly when the magnetizing force is removed, while permanent magnets retain their magnetism over a longer period.

The strength of an electromagnet can be increased by increasing the current flowing through the coil or by increasing the number of wire turns around the core. Both factors enhance the magnetic field strength, as described in the properties of electromagnets.

Aluminum is a non-magnetic material, meaning it cannot be attracted to magnets. In contrast, iron, cobalt, and nickel are magnetic materials and can be attracted by magnets.

Magnetic lines of force represent the strength and direction of a magnet's magnetic field. The density of these lines indicates the strength of the field, with closer lines signifying a stronger magnetic force.

The single touch method involves moving the north pole of a bar magnet along an iron object in one direction to magnetize it. This process aligns the magnetic domains within the iron, creating a magnet.

The primary purpose of a magnetic compass is to find directions. It utilizes a small magnetic needle that aligns itself with the Earth's magnetic field, indicating north-south orientation.

Magnetic lines of force always form closed loops. They exit from the north pole, curve around, and re-enter at the south pole, illustrating the continuous nature of magnetic fields.

Self-demagnetization refers to the gradual loss of magnetism in a magnet over time, especially if its poles are not kept properly. This process can be slowed by proper storage techniques.

When two like poles of magnets (e.g., two north poles) are brought together, they repel each other. This property is a fundamental characteristic of magnetic interactions.

Permanent magnets are characterized by their ability to retain their magnetism even after the magnetizing force has been removed. This makes them useful in a variety of applications where a constant magnetic field is needed.

At the neutral point between two magnets with like poles facing each other, there are no magnetic lines of force, indicating that the magnetic fields cancel each other out, resulting in a neutral area.

An electromagnet is primarily made by wrapping insulated copper wire around a soft iron core. When electric current flows through the wire, the iron core becomes magnetized, creating a magnetic field.

The geographical north pole is actually located near the Earth's magnetic south pole. This misalignment is due to the Earth's magnetic field being slightly tilted from the geographical axis.

Magnetism is the physical phenomenon that allows magnets to attract materials such as iron, nickel, and cobalt. Ferromagnetism is a specific type of magnetism exhibited by these materials, but the general term for the attractive property is magnetism.

Permanent magnets are widely used in credit cards to store information through magnetic strips. This technology allows for secure data storage and retrieval.

When a magnet is broken, each piece retains its magnetic properties and becomes a smaller magnet with both a north pole and a south pole. This characteristic is a defining property of magnets.

Heating a magnet can demagnetize it by increasing the thermal energy and disrupting the orderly alignment of the magnetic domains, which is essential for maintaining its magnetism.