OCR · GCSE · Physics
Course version: J249 · Version from Sept 2018
Describe the difference between permanent and induced magnets
Full specification wording
Magnets and magnetic fields: describe the difference between permanent and induced magnets
A permanent magnet keeps its own magnetic field all the time, whether or not it is near anything else; a bar magnet or a fridge magnet is an example.
Checked against the OCR J249 specification (opens in a new tab) on .
- Point 2 of 7
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
A permanent magnet keeps its own magnetic field all the time, whether or not it is near anything else; a bar magnet or a fridge magnet is an example. An induced magnet only becomes magnetic while it sits in the magnetic field of another magnet, and it loses its magnetism when that field is removed. A useful example is a steel paper clip: on its own it is not magnetic, but bring it near a permanent magnet and it is attracted and behaves like a magnet for as long as it stays in the field. Induced magnetism always produces attraction towards the inducing magnet, never repulsion. A question may ask you to choose the correct description or to decide which material is permanent and which is induced, so focus on whether the magnetism is there all the time or only while another magnet is nearby.
What earns the marks
- States that a permanent magnet produces its own magnetic field all the time.
- States that an induced magnet is only magnetic while it is in the magnetic field of another magnet.
- States that an induced magnet loses its magnetism when the external field is removed.
- Recognises that an induced magnet is always attracted towards the magnet that induces it.
- Distinguishes a permanent magnet from an induced magnet by whether the magnetism persists without another magnet present.
Common mistakes and how to put them right
Describes an induced magnet as keeping its magnetism after the other magnet is removed.
Put it right by stating that induced magnetism lasts only while the external field is present.
Claims that an induced magnet can be repelled by the inducing magnet.
Put it right by stating that induced magnetism always gives attraction.
Treats a permanent magnet as needing another magnet nearby to be magnetic.
Put it right by stating that a permanent magnet has its own field at all times.
Exam tips
- Ask yourself whether the object is magnetic on its own; if it needs another magnet nearby, it is induced.
- Remember that induced magnetism only ever causes attraction, so reject any option describing repulsion of an induced magnet.
- Use a concrete example such as a steel paper clip near a bar magnet to check each option.
Try the lesson
The start of the Magnets and magnetic fields: describe the difference between permanent and induced magnets lesson, made from checked teaching notes for this specification point.
Have a go first
Which object is an example of an induced magnet while it is in use?
Listen
A permanent magnet keeps its own magnetic field all the time, whether or not it is near anything else; a bar magnet or a fridge magnet is an example. An induced magnet only becomes magnetic while it sits in the magnetic field of another magnet, and it loses its magnetism when that field is removed. A useful example is a steel paper clip: on its own it is not magnetic, but bring it near a permanent magnet and it is attracted and behaves like a magnet for as long as it stays in the field. Induced magnetism always produces attraction towards the inducing magnet, never repulsion. A question may ask you to choose the correct description or to decide which material is permanent and which is induced, so focus on whether the magnetism is there all the time or only while another magnet is nearby. A strong answer earns marks for these points. States that a permanent magnet produces its own magnetic field all the time. States that an induced magnet is only magnetic while it is in the magnetic field of another magnet. States that an induced magnet loses its magnetism when the external field is removed. Recognises that an induced magnet is always attracted towards the magnet that induces it. A common slip: Describes an induced magnet as keeping its magnetism after the other magnet is removed. Instead, stating that induced magnetism lasts only while the external field is present. Exam tip: Ask yourself whether the object is magnetic on its own; if it needs another magnet nearby, it is induced.
Key words
Say what each word means before you turn the card.
Permanent magnets
Try answering aloud or in your head before turning the card.
Induced magnets
Try answering aloud or in your head before turning the card.
Attraction caused by induced magnetism
Try answering aloud or in your head before turning the card.
See every definition
- Permanent magnets
- A magnet that keeps its own magnetic field all the time, whether or not it is near anything else.
- Induced magnets
- A magnet that only becomes magnetic while it sits in the magnetic field of another magnet, and loses its magnetism when that field is removed.
- Attraction caused by induced magnetism
- Induced magnetism always produces attraction towards the inducing magnet, never repulsion.
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of Magnets and magnetic fields: describe the difference between permanent and induced magnets
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge