Mains Electricity
Overview
The electricity that powers your home, school and workplace arrives through the mains supply. It is far more powerful than a battery, which is why every plug and appliance includes safety features designed to prevent electric shock and fire.
In this lesson you will learn the difference between a.c. and d.c., how the UK mains supply works, why plugs have three pins, how fuses and circuit breakers protect you, and how to calculate electrical power and energy transferred using the equations P = IV and E = Pt.
Objectives
- Know and use the relationship between power, current and voltage: P = I x V
- Know the difference between mains electricity being alternating current (a.c.) and direct current (d.c.) being supplied by a cell or battery
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Mains Electricity. 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.
- Mains electricity in the UK is: A) D.C. at 12 V B) A.C. at 230 V C) D.C. at 230 V D) A.C. at 12 V Answer: B
- The live wire in a three-pin plug is coloured: A) Blue B) Green and yellow C) Brown D) Red Answer: C
- A fuse protects a circuit by: A) Increasing the resistance B) Melting and breaking the circuit when current is too high C) Reducing the voltage D) Reversing the current direction Answer: B
- A double-insulated appliance does not need: A) A plug B) A live wire C) An earth wire D) A neutral wire Answer: C
- P = IV. A 460 W appliance on 230 V draws a current of: A) 0.5 A B) 2 A C) 20 A D) 105 800 A 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 Mains Electricity? Download the Green Bridge CBT app to access mock questions and full practice assessments for this topic.
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