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54
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20 Jan 2026
•
Magnetism and Electromagnetism Explained
Charlotte
@charlotte26
1 / 5
Magnetism Basics
Think of magnets as having two distinct personalities at opposite ends - the north pole and south pole. Just like people, opposites attract whilst similar personalities clash.
Like poles repel whilst unlike poles attract . The magnetic force is strongest right at the poles and works as a non-contact force - meaning magnets don't need to touch to affect each other.
Only certain metals respond to magnets: iron, steel, cobalt and nickel. These are called magnetic materials, and they're the reason your steel scissors stick to a magnet but your plastic ruler doesn't.
Key Tip: The magnetic force gets weaker as you move further from the poles - that's why magnets work best when they're close together.
Types of Magnets
Permanent magnets are like that reliable friend who never changes. Made from magnetic materials, they always maintain their magnetic properties and constantly produce their own magnetic field.
Induced magnets are more like fair-weather friends - they only become magnetic when placed near another magnet. Remove the magnetic field, and they quickly lose their magnetism.
This difference explains why some materials become temporarily magnetic when near a magnet but return to normal when moved away.
Remember: Permanent magnets keep their magnetism; induced magnets only "borrow" it temporarily.
Magnetic Fields and Testing
To test if something is truly magnetic, try this: a permanent magnet can both attract AND repel other magnets, but it can only attract magnetic materials. If it repels, you've definitely got a magnet on your hands.
Magnetic fields are invisible areas around magnets where their force operates. We can detect these using a magnetic compass - essentially a tiny bar magnet that rotates to point towards magnetic north.
Electromagnets (also called solenoids) are brilliant because you can switch them on and off. They're made by wrapping wire in a coil and passing current through it. Add an iron core, and you've massively boosted the magnetic field strength.
Cool Fact: Earth itself is like a giant magnet with an iron and nickel core, which is why compasses work!
The Motor Effect and Electric Motors
The motor effect might sound complicated, but it's actually quite straightforward - when you pass current through a wire in a magnetic field, the wire experiences a force that pushes it at right angles.
This force follows the equation: force = magnetic flux density × current × length. More current or stronger magnetic field equals more force.
Electric motors use this principle brilliantly. A coil of wire sits in a magnetic field, and when current flows through it, the coil rotates. The clever bit is the commutator - it switches the current direction every half turn, keeping the motor spinning in the same direction.
Real-World Connection: This same principle powers everything from your electric toothbrush to electric cars!
Fleming's Left Hand Rule and Transformers
Fleming's left hand rule is your go-to memory aid for working out directions in the motor effect. Your thumb shows movement direction, forefinger shows the magnetic field (north to south), and your second finger shows current direction (positive to negative).
The force is strongest when current flows at 90° to the magnetic field. If they're parallel, there's no motor effect at all.
Transformers are incredibly useful devices that change voltage in alternating current. They use two coils wound around an iron core - when alternating current flows through the primary coil, it creates a changing magnetic field that induces a different voltage in the secondary coil.
Essential Knowledge: Transformers only work with alternating current because they need the constantly changing magnetic field to function.
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Anna
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Best app on earth! no words because it’s too good
Thomas R
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Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
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Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Magnetism and Electromagnetism Explained
Charlotte
@charlotte26
Magnetism is everywhere around us - from the magnets on your fridge to the motors in your phone's vibration. Understanding how magnets work and how electricity can create magnetic fields opens up a whole world of physics that powers most... Show more
Magnetism Basics
Think of magnets as having two distinct personalities at opposite ends - the north pole and south pole. Just like people, opposites attract whilst similar personalities clash.
Like poles repel whilst unlike poles attract . The magnetic force is strongest right at the poles and works as a non-contact force - meaning magnets don't need to touch to affect each other.
Only certain metals respond to magnets: iron, steel, cobalt and nickel. These are called magnetic materials, and they're the reason your steel scissors stick to a magnet but your plastic ruler doesn't.
Key Tip: The magnetic force gets weaker as you move further from the poles - that's why magnets work best when they're close together.
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Types of Magnets
Permanent magnets are like that reliable friend who never changes. Made from magnetic materials, they always maintain their magnetic properties and constantly produce their own magnetic field.
Induced magnets are more like fair-weather friends - they only become magnetic when placed near another magnet. Remove the magnetic field, and they quickly lose their magnetism.
This difference explains why some materials become temporarily magnetic when near a magnet but return to normal when moved away.
Remember: Permanent magnets keep their magnetism; induced magnets only "borrow" it temporarily.
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Magnetic Fields and Testing
To test if something is truly magnetic, try this: a permanent magnet can both attract AND repel other magnets, but it can only attract magnetic materials. If it repels, you've definitely got a magnet on your hands.
Magnetic fields are invisible areas around magnets where their force operates. We can detect these using a magnetic compass - essentially a tiny bar magnet that rotates to point towards magnetic north.
Electromagnets (also called solenoids) are brilliant because you can switch them on and off. They're made by wrapping wire in a coil and passing current through it. Add an iron core, and you've massively boosted the magnetic field strength.
Cool Fact: Earth itself is like a giant magnet with an iron and nickel core, which is why compasses work!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The Motor Effect and Electric Motors
The motor effect might sound complicated, but it's actually quite straightforward - when you pass current through a wire in a magnetic field, the wire experiences a force that pushes it at right angles.
This force follows the equation: force = magnetic flux density × current × length. More current or stronger magnetic field equals more force.
Electric motors use this principle brilliantly. A coil of wire sits in a magnetic field, and when current flows through it, the coil rotates. The clever bit is the commutator - it switches the current direction every half turn, keeping the motor spinning in the same direction.
Real-World Connection: This same principle powers everything from your electric toothbrush to electric cars!
Sign up to see the contentIt's free!
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Join milions of students
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Fleming's Left Hand Rule and Transformers
Fleming's left hand rule is your go-to memory aid for working out directions in the motor effect. Your thumb shows movement direction, forefinger shows the magnetic field (north to south), and your second finger shows current direction (positive to negative).
The force is strongest when current flows at 90° to the magnetic field. If they're parallel, there's no motor effect at all.
Transformers are incredibly useful devices that change voltage in alternating current. They use two coils wound around an iron core - when alternating current flows through the primary coil, it creates a changing magnetic field that induces a different voltage in the secondary coil.
Essential Knowledge: Transformers only work with alternating current because they need the constantly changing magnetic field to function.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
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4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user