Maths
Chemistry
Biology
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
Show all topics
Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
World war one
Britain: 1509 -1745
Show all topics
Physics
15 Dec 2025
377
3 pages
Katie Gunn @kgunn15
The electromagnetic spectrum and radiation are fascinating areas of physics that explain how energy moves around us. From... Show more
Ever wonder why microwaves cook food but radio waves don't? The electromagnetic (EM) spectrum explains this! It's a family of waves with different energy levels and uses.
Radio waves have the lowest energy and are used for communication. They're completely harmless to humans. Microwaves, with slightly more energy, help cook your food and carry mobile phone signals.
Infrared (IR) radiation is used in thermal imaging, cooking, and burglar alarms. While invisible, these waves can cause burns when intense. Visible light is the only part of the spectrum we can actually see - it's how you're reading this right now!
Ultraviolet (UV) radiation has enough energy to kill bacteria and is used to check for forged money. However, too much exposure can cause skin cancer and eye damage. X-rays can see through your skin but not dense bones, making them perfect for medical imaging and airport security.
Remember this As you move from radio waves to gamma rays, the energy increases while wavelength decreases. All electromagnetic waves are transverse waves that travel at the same speed in a vacuum!
At the highest energy end, gamma rays can sterilise medical equipment and treat cancer, though ironically, they can also cause cancer with excessive exposure.
Radiation is simply energy emitted from a point. Some types, called ionising radiation, can change atoms by giving them an electrical charge – this is where things get interesting!
Atoms normally have a perfect balance of positive protons and negative electrons, making them electrically neutral. For example, a lithium atom has a mass of 7 and contains protons (mass 1, positive charge), neutrons (mass 1, no charge), and electrons (tiny mass, negative charge).
When ionising radiation hits an atom, it can knock out an electron. This creates an ion - an atom with an unbalanced charge. Since it lost a negative electron, the atom becomes positively charged. This process can damage living cells, which is why safety precautions are so important.
Safety first! When handling radioactive materials, always use tongs (never touch directly), keep samples in shielded containers , and minimise your exposure time.
These safety measures protect us from the harmful effects that ionising radiation can have on our bodies.
When unstable atoms break down, they release different types of radiation. This breakdown is fascinating because it actually changes one element into another!
Alpha radiation happens when an unstable nucleus ejects an alpha particle (two protons and two neutrons). This creates a new atom with less mass than the original. Alpha particles are relatively large and can be stopped by something as thin as paper.
Beta radiation occurs when a neutron in the nucleus changes into a proton and an electron. The high-energy electron shoots out as a beta particle, creating a new element with the same mass but different properties. Beta particles can penetrate paper but are stopped by aluminum.
Gamma radiation is different - it's pure energy with no mass or charge. It often accompanies alpha or beta decay when the nucleus has excess energy to release. Gamma rays are the most penetrating form of radiation and require thick lead or concrete to block.
Did you know? Scientists can write nuclear decay equations to show exactly how one element changes into another during radioactive decay. These equations always balance - just like in chemistry!
Understanding these forms of radiation helps scientists develop medical treatments, energy sources, and important industrial tools.
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the fundamentals of electromagnetic waves, including the electromagnetic spectrum, wave properties, and applications in technology and medicine. This comprehensive guide covers key concepts such as refraction, radiation types, and the behavior of light and sound. Ideal for students preparing for exams in physics, this resource includes diagrams, calculations, and practical examples to enhance understanding.
PhysicsGood
PhysicsThis involves concepts in electromagnetic spectrum and its classifications.
PhysicsWAVES (paper 2 AQA)
PhysicsPhysics, The Electromagnetic Spectrum with answers and corrections
PhysicsExplore the visible light spectrum, including the properties of colors, how objects appear based on light interaction, and the function of color filters. This summary covers key concepts such as opaque, transparent, and translucent materials, and the science behind color perception. Ideal for students studying light phenomena.
PhysicsQuotes from every main character
English LiteratureApp Store
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 THE SCHOOLGPT. 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 THE SCHOOLGPT. 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
Katie Gunn
@kgunn15
The electromagnetic spectrum and radiation are fascinating areas of physics that explain how energy moves around us. From radio waves to gamma rays, these forms of energy impact our daily lives in countless ways - from how we cook food... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wonder why microwaves cook food but radio waves don't? The electromagnetic (EM) spectrum explains this! It's a family of waves with different energy levels and uses.
Radio waves have the lowest energy and are used for communication. They're completely harmless to humans. Microwaves, with slightly more energy, help cook your food and carry mobile phone signals.
Infrared (IR) radiation is used in thermal imaging, cooking, and burglar alarms. While invisible, these waves can cause burns when intense. Visible light is the only part of the spectrum we can actually see - it's how you're reading this right now!
Ultraviolet (UV) radiation has enough energy to kill bacteria and is used to check for forged money. However, too much exposure can cause skin cancer and eye damage. X-rays can see through your skin but not dense bones, making them perfect for medical imaging and airport security.
Remember this: As you move from radio waves to gamma rays, the energy increases while wavelength decreases. All electromagnetic waves are transverse waves that travel at the same speed in a vacuum!
At the highest energy end, gamma rays can sterilise medical equipment and treat cancer, though ironically, they can also cause cancer with excessive exposure.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Radiation is simply energy emitted from a point. Some types, called ionising radiation, can change atoms by giving them an electrical charge – this is where things get interesting!
Atoms normally have a perfect balance of positive protons and negative electrons, making them electrically neutral. For example, a lithium atom has a mass of 7 and contains protons (mass 1, positive charge), neutrons (mass 1, no charge), and electrons (tiny mass, negative charge).
When ionising radiation hits an atom, it can knock out an electron. This creates an ion - an atom with an unbalanced charge. Since it lost a negative electron, the atom becomes positively charged. This process can damage living cells, which is why safety precautions are so important.
Safety first! When handling radioactive materials, always use tongs (never touch directly), keep samples in shielded containers , and minimise your exposure time.
These safety measures protect us from the harmful effects that ionising radiation can have on our bodies.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
When unstable atoms break down, they release different types of radiation. This breakdown is fascinating because it actually changes one element into another!
Alpha radiation happens when an unstable nucleus ejects an alpha particle (two protons and two neutrons). This creates a new atom with less mass than the original. Alpha particles are relatively large and can be stopped by something as thin as paper.
Beta radiation occurs when a neutron in the nucleus changes into a proton and an electron. The high-energy electron shoots out as a beta particle, creating a new element with the same mass but different properties. Beta particles can penetrate paper but are stopped by aluminum.
Gamma radiation is different - it's pure energy with no mass or charge. It often accompanies alpha or beta decay when the nucleus has excess energy to release. Gamma rays are the most penetrating form of radiation and require thick lead or concrete to block.
Did you know? Scientists can write nuclear decay equations to show exactly how one element changes into another during radioactive decay. These equations always balance - just like in chemistry!
Understanding these forms of radiation helps scientists develop medical treatments, energy sources, and important industrial tools.
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the fundamentals of electromagnetic waves, including the electromagnetic spectrum, wave properties, and applications in technology and medicine. This comprehensive guide covers key concepts such as refraction, radiation types, and the behavior of light and sound. Ideal for students preparing for exams in physics, this resource includes diagrams, calculations, and practical examples to enhance understanding.
PhysicsGood
PhysicsThis involves concepts in electromagnetic spectrum and its classifications.
PhysicsWAVES (paper 2 AQA)
PhysicsPhysics, The Electromagnetic Spectrum with answers and corrections
PhysicsExplore the visible light spectrum, including the properties of colors, how objects appear based on light interaction, and the function of color filters. This summary covers key concepts such as opaque, transparent, and translucent materials, and the science behind color perception. Ideal for students studying light phenomena.
PhysicsQuotes from every main character
English LiteratureApp Store
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 THE SCHOOLGPT. 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 THE SCHOOLGPT. 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
Sociology