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Abby
28/11/2025
Physics
Physics triple science notes on Electricity and Energy Stores
185
•
28 Nov 2025
•
Complete Physics Notes on Electricity and Energy Stores
Abby
@abbywade
1 / 7
Energy Stores and Systems
Think of energy like money in different bank accounts - it can move between accounts but never disappears completely. There are eight main energy stores you need to know: kinetic (movement), gravitational potential (height), elastic potential (stretched springs), thermal (heat), chemical , magnetic, electrostatic, and nuclear.
Energy transfers happen in four ways. Mechanical work occurs when forces move objects through distances. Electrical work happens when charges flow due to voltage differences. Heating transfers energy due to temperature differences. Radiation sends energy as waves like light and infrared from the sun.
The conservation of energy is physics' golden rule: energy can transfer between stores or dissipate (get wasted), but it can never be created or destroyed. When energy gets "wasted," it usually becomes heat that spreads into the surroundings and becomes less useful.
Key insight: Every device wastes some energy - LED bulbs waste less than old filament bulbs, which is why they're more efficient and cheaper to run.
Energy in Action and Work Done
Real-world examples show energy conservation perfectly. When a skydiver jumps, gravitational potential energy converts to kinetic energy as they fall faster. Some energy dissipates as heat to surrounding air particles. Your smartphone converts chemical energy from the battery into electrical work, then into light for the screen, sound waves, and waste heat.
Work done measures energy transfer when forces move objects through distances. The formula is simple: work done = force × distance. This directly equals the energy transferred, making it a crucial concept for calculations.
Power tells you how quickly energy transfers happen. More powerful devices transfer more energy each second. Power = work done ÷ time, or power = current × voltage. One watt equals one joule per second.
Remember: The bigger the force and the further it moves something, the more work gets done and energy gets transferred.
Efficiency and Energy Resources
Efficiency measures how good devices are at avoiding energy waste. Calculate it as: useful energy out ÷ total energy in, then multiply by 100 for percentage. Perfect efficiency (100%) is impossible because all devices waste some energy through friction, electrical resistance, or unwanted sound.
Our major energy resources include fossil fuels, nuclear fuel, and renewables like wind, solar, and hydroelectric power. Energy demand varies throughout the day and seasons - more heating in winter, peak electricity use in early evenings when everyone's home.
Renewable resources like hydroelectricity and wind power don't run out but often have lower power output and depend on weather conditions. Non-renewable resources like fossil fuels and nuclear provide reliable, high power output but cause environmental problems or produce dangerous waste.
Think about it: Your energy choices matter - switching to LED bulbs or supporting renewable energy reduces environmental impact and often saves money long-term.
Comparing Energy Resources
Fossil fuels remain popular because they're incredibly reliable - power stations can run almost continuously and gas stations can start up quickly when extra power's needed. However, they release CO₂, contributing to climate change, and they'll eventually run out.
Nuclear power provides massive energy output and doesn't emit CO₂ during operation. The downsides include expensive construction and decommissioning costs, plus the challenge of safely disposing of radioactive waste that remains dangerous for thousands of years.
Renewable sources have no fuel costs once built but require significant upfront investment. Wind and solar depend on weather conditions, making them less reliable than fossil fuels. However, they're becoming increasingly popular as technology improves and costs decrease.
Future focus: Many countries are investing heavily in renewable energy storage solutions to overcome reliability issues and reduce dependence on fossil fuels.
Electricity Fundamentals
Electric current flows when charges move through circuits. Direct current (DC) flows in one direction, like from batteries. Alternating current (AC) constantly reverses direction, like mains electricity in your home. Current needs a complete circuit and a potential difference (voltage) to push charges around.
The fundamental relationships you need are: V = I × R , P = I × V , and Q = I × t . These equations solve most electrical problems you'll encounter.
Resistance opposes current flow. Ohmic conductors have constant resistance, but filament bulbs increase resistance as they heat up. Diodes only allow current in one direction, while thermistors and LDRs change resistance with temperature and light respectively.
Ohm's Law: For many materials, voltage and current are directly proportional - double the voltage, double the current (if temperature stays constant).
Circuits and Electric Forces
Series circuits connect components in a single loop - if one breaks, everything stops working. Current stays the same throughout, but voltage splits across components. Total resistance equals the sum of individual resistances.
Parallel circuits provide multiple paths for current. If one component fails, others keep working. Voltage stays the same across each branch, but current splits between paths. Total resistance is always less than the smallest individual resistance.
Electric forces work like magnetic forces - opposite charges attract, same charges repel. These non-contact forces act at a distance and get stronger when charges are closer together or larger.
Circuit tip: Christmas lights wired in series all go out when one bulb fails, but parallel-wired lights keep working. This explains why modern LED strings often use parallel circuits.
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Best app on earth! no words because it’s too good
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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.
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
Complete Physics Notes on Electricity and Energy Stores
Abby
@abbywade
Energy and electricity are fundamental concepts that explain how the world around you works. From your smartphone battery to renewable energy sources, understanding these principles helps make sense of everything from why LED bulbs save money to how power stations... Show more
Energy Stores and Systems
Think of energy like money in different bank accounts - it can move between accounts but never disappears completely. There are eight main energy stores you need to know: kinetic (movement), gravitational potential (height), elastic potential (stretched springs), thermal (heat), chemical , magnetic, electrostatic, and nuclear.
Energy transfers happen in four ways. Mechanical work occurs when forces move objects through distances. Electrical work happens when charges flow due to voltage differences. Heating transfers energy due to temperature differences. Radiation sends energy as waves like light and infrared from the sun.
The conservation of energy is physics' golden rule: energy can transfer between stores or dissipate (get wasted), but it can never be created or destroyed. When energy gets "wasted," it usually becomes heat that spreads into the surroundings and becomes less useful.
Key insight: Every device wastes some energy - LED bulbs waste less than old filament bulbs, which is why they're more efficient and cheaper to run.
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Energy in Action and Work Done
Real-world examples show energy conservation perfectly. When a skydiver jumps, gravitational potential energy converts to kinetic energy as they fall faster. Some energy dissipates as heat to surrounding air particles. Your smartphone converts chemical energy from the battery into electrical work, then into light for the screen, sound waves, and waste heat.
Work done measures energy transfer when forces move objects through distances. The formula is simple: work done = force × distance. This directly equals the energy transferred, making it a crucial concept for calculations.
Power tells you how quickly energy transfers happen. More powerful devices transfer more energy each second. Power = work done ÷ time, or power = current × voltage. One watt equals one joule per second.
Remember: The bigger the force and the further it moves something, the more work gets done and energy gets transferred.
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Efficiency and Energy Resources
Efficiency measures how good devices are at avoiding energy waste. Calculate it as: useful energy out ÷ total energy in, then multiply by 100 for percentage. Perfect efficiency (100%) is impossible because all devices waste some energy through friction, electrical resistance, or unwanted sound.
Our major energy resources include fossil fuels, nuclear fuel, and renewables like wind, solar, and hydroelectric power. Energy demand varies throughout the day and seasons - more heating in winter, peak electricity use in early evenings when everyone's home.
Renewable resources like hydroelectricity and wind power don't run out but often have lower power output and depend on weather conditions. Non-renewable resources like fossil fuels and nuclear provide reliable, high power output but cause environmental problems or produce dangerous waste.
Think about it: Your energy choices matter - switching to LED bulbs or supporting renewable energy reduces environmental impact and often saves money long-term.
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Comparing Energy Resources
Fossil fuels remain popular because they're incredibly reliable - power stations can run almost continuously and gas stations can start up quickly when extra power's needed. However, they release CO₂, contributing to climate change, and they'll eventually run out.
Nuclear power provides massive energy output and doesn't emit CO₂ during operation. The downsides include expensive construction and decommissioning costs, plus the challenge of safely disposing of radioactive waste that remains dangerous for thousands of years.
Renewable sources have no fuel costs once built but require significant upfront investment. Wind and solar depend on weather conditions, making them less reliable than fossil fuels. However, they're becoming increasingly popular as technology improves and costs decrease.
Future focus: Many countries are investing heavily in renewable energy storage solutions to overcome reliability issues and reduce dependence on fossil fuels.
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Electricity Fundamentals
Electric current flows when charges move through circuits. Direct current (DC) flows in one direction, like from batteries. Alternating current (AC) constantly reverses direction, like mains electricity in your home. Current needs a complete circuit and a potential difference (voltage) to push charges around.
The fundamental relationships you need are: V = I × R , P = I × V , and Q = I × t . These equations solve most electrical problems you'll encounter.
Resistance opposes current flow. Ohmic conductors have constant resistance, but filament bulbs increase resistance as they heat up. Diodes only allow current in one direction, while thermistors and LDRs change resistance with temperature and light respectively.
Ohm's Law: For many materials, voltage and current are directly proportional - double the voltage, double the current (if temperature stays constant).
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Circuits and Electric Forces
Series circuits connect components in a single loop - if one breaks, everything stops working. Current stays the same throughout, but voltage splits across components. Total resistance equals the sum of individual resistances.
Parallel circuits provide multiple paths for current. If one component fails, others keep working. Voltage stays the same across each branch, but current splits between paths. Total resistance is always less than the smallest individual resistance.
Electric forces work like magnetic forces - opposite charges attract, same charges repel. These non-contact forces act at a distance and get stronger when charges are closer together or larger.
Circuit tip: Christmas lights wired in series all go out when one bulb fails, but parallel-wired lights keep working. This explains why modern LED strings often use parallel circuits.
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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?
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Chemistry paper 1 aqa
This is the aqa exam board for triple highwe
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Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
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 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