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Waffle ๐ด๐ต๐ธ
22/11/2025
Physics
GCSE EM Waves
208
โข
22 Nov 2025
โข
GCSE Electromagnetic Waves Study Guide
Waffle ๐ด๐ต๐ธ
@amuslimah
1 / 4
Understanding Electromagnetic Waves and Radiation Safety
Electromagnetic waves are created when atoms or their nuclei change - think of gamma rays bursting from radioactive atoms or radio waves generated by electrical circuits in your phone's transmitter. These waves are absolutely everywhere and power most of the technology you use daily.
When it comes to safety, some EM waves can be dangerous. Ionising radiation like X-rays and gamma rays pack enough energy to knock electrons off atoms, potentially damaging your DNA and increasing cancer risk. That's why we measure radiation dose in sieverts - it tells us how risky exposure actually is.
The most dangerous waves are ultraviolet (hello, sunburn and skin cancer), X-rays, and gamma rays. However, many EM waves are completely safe - radio waves bounce harmlessly off your body, while microwaves in your oven only heat water molecules in food.
Quick Safety Tip: The higher the frequency of EM waves, the more energy they carry and the more dangerous they become to living tissue.
Wave Properties and the EM Spectrum
All electromagnetic waves are transverse waves that transfer energy at the speed of light through space. They can be reflected (bouncing off surfaces), refracted (bending when entering new materials), absorbed (energy converted to heat), or transmitted (passing straight through).
The EM spectrum runs from radio waves (longest wavelength, lowest frequency) through microwaves, infrared, visible light, ultraviolet, X-rays, to gamma rays (shortest wavelength, highest frequency). Remember: longer wavelength always means lower frequency.
Refraction happens because waves slow down in denser materials, causing them to bend towards the normal (an imaginary line perpendicular to the surface). This is why a straw looks bent in water - light waves change direction as they move from water to air.
Memory Trick: "Really Mad Insects Vex Ugly eXtra-terrestrial Gorillas" helps you remember the EM spectrum order from longest to shortest wavelength.
Practical Applications and Investigations
EM waves power our modern world in countless ways. Radio waves carry TV and Bluetooth signals, microwaves enable satellite communication and cook your food by vibrating water molecules, and infrared radiation lets you feel warmth from heaters and enables night-vision cameras.
Visible light travels through fibre optic cables to bring you super-fast internet, while X-rays help doctors spot broken bones because they pass through soft tissue but not bone. Gamma rays can destroy cancer cells in radiotherapy treatments.
In lab investigations, you'll explore how different surfaces affect reflection and refraction using ray boxes and glass blocks. You'll also discover that matt black surfaces are brilliant at absorbing and emitting infrared radiation, whilst shiny surfaces reflect most radiation away.
Real-World Connection: The Leslie cube experiment explains why car radiators are painted black (better heat emission) and why emergency blankets are shiny (reflecting body heat back to you).
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4.9/5
App Store
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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
GCSE Electromagnetic Waves Study Guide
Waffle ๐ด๐ต๐ธ
@amuslimah
Electromagnetic waves are everywhere around you - from the radio signals carrying your favourite songs to the microwaves heating your food and the visible light helping you read this! Understanding how these invisible waves work will help you grasp everything... Show more
Understanding Electromagnetic Waves and Radiation Safety
Electromagnetic waves are created when atoms or their nuclei change - think of gamma rays bursting from radioactive atoms or radio waves generated by electrical circuits in your phone's transmitter. These waves are absolutely everywhere and power most of the technology you use daily.
When it comes to safety, some EM waves can be dangerous. Ionising radiation like X-rays and gamma rays pack enough energy to knock electrons off atoms, potentially damaging your DNA and increasing cancer risk. That's why we measure radiation dose in sieverts - it tells us how risky exposure actually is.
The most dangerous waves are ultraviolet (hello, sunburn and skin cancer), X-rays, and gamma rays. However, many EM waves are completely safe - radio waves bounce harmlessly off your body, while microwaves in your oven only heat water molecules in food.
Quick Safety Tip: The higher the frequency of EM waves, the more energy they carry and the more dangerous they become to living tissue.
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
Wave Properties and the EM Spectrum
All electromagnetic waves are transverse waves that transfer energy at the speed of light through space. They can be reflected (bouncing off surfaces), refracted (bending when entering new materials), absorbed (energy converted to heat), or transmitted (passing straight through).
The EM spectrum runs from radio waves (longest wavelength, lowest frequency) through microwaves, infrared, visible light, ultraviolet, X-rays, to gamma rays (shortest wavelength, highest frequency). Remember: longer wavelength always means lower frequency.
Refraction happens because waves slow down in denser materials, causing them to bend towards the normal (an imaginary line perpendicular to the surface). This is why a straw looks bent in water - light waves change direction as they move from water to air.
Memory Trick: "Really Mad Insects Vex Ugly eXtra-terrestrial Gorillas" helps you remember the EM spectrum order from longest to shortest wavelength.
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
Practical Applications and Investigations
EM waves power our modern world in countless ways. Radio waves carry TV and Bluetooth signals, microwaves enable satellite communication and cook your food by vibrating water molecules, and infrared radiation lets you feel warmth from heaters and enables night-vision cameras.
Visible light travels through fibre optic cables to bring you super-fast internet, while X-rays help doctors spot broken bones because they pass through soft tissue but not bone. Gamma rays can destroy cancer cells in radiotherapy treatments.
In lab investigations, you'll explore how different surfaces affect reflection and refraction using ray boxes and glass blocks. You'll also discover that matt black surfaces are brilliant at absorbing and emitting infrared radiation, whilst shiny surfaces reflect most radiation away.
Real-World Connection: The Leslie cube experiment explains why car radiators are painted black (better heat emission) and why emergency blankets are shiny (reflecting body heat back to you).
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
We thought youโd 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?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help โ all at your fingertips.
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4.9/5
App Store
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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