Cells, Batteries, Generators And Motors
Overview
Move a magnet near a coil of wire and a voltage springs up out of nowhere; send a current through a wire and it becomes wrapped in a magnetic field; place that wire in another magnet's field and it is pushed sideways. Electricity and magnetism are two sides of one coin, and this link runs every generator, motor, relay and loudspeaker.
In this topic you will learn how a changing magnetic field induces an e.m.f., what affects its size and direction, the magnetic field patterns around wires and solenoids, and how a simple a.c. generator works. You will also relate the directions of force, field and current, and see the magnetic effect of a current applied in relays and loudspeakers.
Objectives
- [Core] Know that cells and batteries transfer chemical energy into electrical energy
- [Core] Know that generators transfer kinetic energy into electrical energy
- [Core] Know that electric motors transfer electrical energy into kinetic energy
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Cells, Batteries, Generators And Motors. 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.
- An e.m.f. is induced in a coil when: A. a magnet rests inside it B. the magnetic field through it changes C. it is painted black D. it is at a high temperature Answer: B
- Which change does NOT increase the e.m.f. induced in a coil? A. moving the magnet faster B. using more turns C. using a stronger magnet D. holding the magnet still Answer: D
- The magnetic field around a long straight current-carrying wire is: A. straight lines along the wire B. concentric circles around the wire C. a uniform field D. zero Answer: B
- In a simple a.c. generator the induced e.m.f. is greatest when the coil is: A. vertical B. horizontal C. at rest D. removed Answer: B
- The force on a current-carrying wire in a magnetic field is found using: A. the right-hand grip rule B. Fleming's right-hand rule C. Fleming's left-hand rule D. Ohm's law Answer: C
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.
Recommended Books
Practice Mock Questions
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