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magnetic field

Primary Information
Secondary Information

Definition

A magnetic field is a region of space around a magnet where there is a force that can attract or repel other magnets or objects made of magnetic materials. The force of magnetism is caused by the motion of electrons inside the atoms of the material.

The magnetic field around a magnet is strongest at the poles and weakest in the middle. The direction of the magnetic field is indicated by the magnetic field lines. Magnetic field lines always point from the north pole of a magnet to the south pole.

Magnetic fields can be used to do many things, such as:

  • Making compasses work
  • Picking up metal objects
  • Creating electricity
  • Building motors
  • Making MRI machines

How can the word be used?

The current flowing through the wire created a magnetic field.

magnetic field

Different forms of the word

Noun: A region of space around a magnet where the magnetic force is exerted.

Adjective: Describing something that is related to a magnetic field. For example, you could say "magnetic field lines" or "magnetic field strength".

Verb: To create a magnetic field. For example, you could say "The magnetized the needle" or "The current created a magnetic field".

Etymology

The word "magnetic field" comes from the noun "magnet", which is a piece of iron or steel that has been magnetised and has the property of attracting other pieces of iron or steel.

The word "magnetic field" was first used in English in the 17th century. It was originally used to describe the area around a magnet where the magnetic force was exerted, but it soon came to be used in a more general sense to describe any region of space where a magnetic force is present.

Question

What is a magnetic field?

AQA Science Exam Question and Answer

Question:

Describe what a magnetic field is and how it is produced. Explain how magnetic field lines can provide information about the strength and direction of a magnetic field.

Answer:

A magnetic field is a region around a magnet or a current-carrying conductor where the influence of magnetism can be felt. It's an invisible force that can exert attractive or repulsive effects on magnetic materials and other magnets. Magnetic fields are produced by the motion of charged particles, particularly electrons, within atoms.

When a current flows through a wire, it generates a magnetic field around it. The strength of the magnetic field increases with the amount of current flowing through the wire. Similarly, in a permanent magnet, the alignment of atomic spins leads to the creation of a magnetic field.

Magnetic field lines help visualise and understand the properties of magnetic fields. These lines show the direction in which a magnetic north pole would move if placed in the field. The density of the field lines indicates the strength of the field; the closer the lines, the stronger the field. The direction of the field lines shows how the field flows, from the north pole of a magnet to its south pole.

The concept of magnetic field lines is used in various applications, such as designing electromagnetic devices and understanding Earth's magnetic field. They provide a clear representation of the field's properties, helping scientists and engineers work with magnetism effectively.