Open the App

Subjects

Physics

9 Dec 2025

551

1 page

Understanding Energy: Conservation, Dissipation, and Efficiency

user profile picture

Tilly @tillyxxx

Energy is all around us, constantly moving and changing from one form to another - but it's never... Show more

## Conservation and Dissipation
of Energy-

Key Terms:
power = the rate of energy transfer, rate work is done
Efficiency = the measure of ho

Conservation and Dissipation of Energy

Ever wondered why your laptop gets warm when it's charging? That's energy dissipation in action - not all the electrical energy becomes useful stored energy in your battery. Some always gets "wasted" as heat, which is why no energy transfer is ever 100% efficient.

Power tells us how quickly energy moves from one place to another. Think of it like the speed of energy transfer - a high-power appliance like a kettle transfers energy much faster than a low-power LED bulb. This is why your kettle boils water in minutes whilst a small heater takes ages to warm a room.

Efficiency is basically a report card for energy transfers, showing what fraction of input energy actually does something useful. Since energy can't be created or destroyed (it just changes form), improving efficiency means reducing those annoying energy losses - like the heat from your laptop or the sound from a car engine.

Quick Check If a light bulb is 20% efficient, that means 80% of the electrical energy becomes heat instead of light - no wonder old bulbs get so hot!

When dealing with springs and elastic objects, there's a neat relationship double the force, double the extension. This works until you reach the limit of proportionality - push too hard and the spring won't bounce back to its original shape. The spring constant tells you how "stiff" a spring is - a high value means it barely stretches even with lots of force.

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?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

9

Smart Tools NEW

Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines

Mock Exam
Quiz
Flashcards
Essay

Similar content

Physics Energy Concepts

Explore key concepts in physics related to energy, power, and electricity. This resource covers topics such as energy transfer, Ohm's Law, radioactivity, and thermal energy, providing a comprehensive overview for GCSE Triple Science revision. Ideal for students preparing for exams, this summary includes essential equations and principles to enhance understanding.

PhysicsPhysics
11

Zoology Unit 1

Zoology Notes

PhysicsPhysics

Heat Transfer Mechanisms

Explore the fundamental mechanisms of heat transfer: conduction, convection, and radiation. This summary covers how energy is transferred through different mediums, the role of particle movement, and the properties of thermal conductors. Ideal for students studying physics concepts related to thermal energy.

PhysicsPhysics
10

Electricity Fundamentals

Explore the principles of electricity, including potential difference, resistance, and current flow in series and parallel circuits. This summary covers key concepts such as Ohm's law, the behavior of filament lamps, and the role of various circuit components. Ideal for students preparing for assessments in physics.

PhysicsPhysics
10

Energy Resources Overview

Explore the types of energy resources, including renewable and non-renewable sources, their environmental impacts, and applications in transport and heating. This summary covers key concepts such as fossil fuels, biofuels, and sustainable energy solutions, providing a comprehensive understanding for students studying energy resources.

PhysicsPhysics
10

Energy Resources Overview

Explore key concepts of energy resources, including renewable and non-renewable types, their uses, and environmental impacts. This summary covers essential terms like fossil fuels, biofuels, and nuclear energy, providing insights into energy generation methods and their implications for climate change.

PhysicsPhysics
11

Most popular content: Work

Most popular content in Physics

Most popular content

Chemistry paper 1 aqa

This is the aqa exam board for triple highwe

ChemistryChemistry
10

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

 

Physics

551

9 Dec 2025

1 page

Understanding Energy: Conservation, Dissipation, and Efficiency

user profile picture

Tilly

@tillyxxx

Energy is all around us, constantly moving and changing from one form to another - but it's never actually lost or created. Understanding how energy transfers work, why some transfers are more efficient than others, and how forces affect objects... Show more

## Conservation and Dissipation
of Energy-

Key Terms:
power = the rate of energy transfer, rate work is done
Efficiency = the measure of ho

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

Conservation and Dissipation of Energy

Ever wondered why your laptop gets warm when it's charging? That's energy dissipation in action - not all the electrical energy becomes useful stored energy in your battery. Some always gets "wasted" as heat, which is why no energy transfer is ever 100% efficient.

Power tells us how quickly energy moves from one place to another. Think of it like the speed of energy transfer - a high-power appliance like a kettle transfers energy much faster than a low-power LED bulb. This is why your kettle boils water in minutes whilst a small heater takes ages to warm a room.

Efficiency is basically a report card for energy transfers, showing what fraction of input energy actually does something useful. Since energy can't be created or destroyed (it just changes form), improving efficiency means reducing those annoying energy losses - like the heat from your laptop or the sound from a car engine.

Quick Check: If a light bulb is 20% efficient, that means 80% of the electrical energy becomes heat instead of light - no wonder old bulbs get so hot!

When dealing with springs and elastic objects, there's a neat relationship: double the force, double the extension. This works until you reach the limit of proportionality - push too hard and the spring won't bounce back to its original shape. The spring constant tells you how "stiff" a spring is - a high value means it barely stretches even with lots of force.

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?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

9

Smart Tools NEW

Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines

Mock Exam
Quiz
Flashcards
Essay

Similar content

Physics Energy Concepts

Explore key concepts in physics related to energy, power, and electricity. This resource covers topics such as energy transfer, Ohm's Law, radioactivity, and thermal energy, providing a comprehensive overview for GCSE Triple Science revision. Ideal for students preparing for exams, this summary includes essential equations and principles to enhance understanding.

PhysicsPhysics
11

Zoology Unit 1

Zoology Notes

PhysicsPhysics

Heat Transfer Mechanisms

Explore the fundamental mechanisms of heat transfer: conduction, convection, and radiation. This summary covers how energy is transferred through different mediums, the role of particle movement, and the properties of thermal conductors. Ideal for students studying physics concepts related to thermal energy.

PhysicsPhysics
10

Electricity Fundamentals

Explore the principles of electricity, including potential difference, resistance, and current flow in series and parallel circuits. This summary covers key concepts such as Ohm's law, the behavior of filament lamps, and the role of various circuit components. Ideal for students preparing for assessments in physics.

PhysicsPhysics
10

Energy Resources Overview

Explore the types of energy resources, including renewable and non-renewable sources, their environmental impacts, and applications in transport and heating. This summary covers key concepts such as fossil fuels, biofuels, and sustainable energy solutions, providing a comprehensive understanding for students studying energy resources.

PhysicsPhysics
10

Energy Resources Overview

Explore key concepts of energy resources, including renewable and non-renewable types, their uses, and environmental impacts. This summary covers essential terms like fossil fuels, biofuels, and nuclear energy, providing insights into energy generation methods and their implications for climate change.

PhysicsPhysics
11

Most popular content: Work

Most popular content in Physics

Most popular content

Chemistry paper 1 aqa

This is the aqa exam board for triple highwe

ChemistryChemistry
10

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