Energy Transfers
Overview
Every machine, every organism and every star runs on energy transfers. The physics of where energy sits, how it moves and how much of it ends up doing something useful is one of the most practical topics you will study.
In this lesson you will meet the eight energy stores, the four transfer pathways, the conservation principle, efficiency calculations with Sankey diagrams, and the three mechanisms by which thermal energy spreads - conduction, convection and radiation - together with ways to slow them down.
Objectives
- Describe energy transfers involving energy stores: chemical, kinetic, gravitational, elastic, thermal, magnetic, electrostatic, nuclear
- Use the principle of conservation of energy
- Know and use the relationship between efficiency, useful energy output and total energy output
- Describe a variety of everyday and scientific devices explaining the transfer of energy, including Sankey diagrams
- Describe how thermal energy transfer may take place by conduction, convection and radiation
- Explain the role of convection in everyday phenomena
- Explain how emission and absorption of radiation are related to surface and temperature
- Investigate thermal energy transfer by conduction, convection and radiation
- Explain ways of reducing unwanted energy transfer such as insulation
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Energy Transfers. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which of the following is NOT an energy store? A) Chemical B) Electrical C) Kinetic D) Nuclear Answer: B
- A device receives 400 J and outputs 300 J usefully. Its efficiency is: A) 75% B) 133% C) 25% D) 100% Answer: A
- Which thermal transfer mechanism works through a vacuum? A) Conduction B) Convection C) Radiation D) All three Answer: C
- In a Sankey diagram, the width of an arrow represents: A) Speed B) Temperature C) Amount of energy D) Type of store Answer: C
- Cavity wall insulation mainly reduces: A) Radiation through walls B) Convection and conduction in the wall cavity C) Sound transfer D) Light transfer Answer: B
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Practice Mock Questions
Want to practice mock questions on Energy Transfers? Download the Green Bridge CBT app to access mock questions and full practice assessments for this topic.
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