Electromagnetism · SHS2 Physics

Lesson notes

Learning Objectives

Indicator: 2.3.2.LI.4 - Describe the electromagnetic switches and applications.

By the end of the lesson, learners can:

Draw and label the constructional parts of an electromagnetic switch, namely the coil, core, armature, contacts, and return spring.
Explain the working principle of an electromagnetic switch, describing how current in the coil produces a magnetic field that attracts the armature.
Distinguish between electromagnetic switches and ordinary manual switches, citing at least two differences.
Identify at least four real-life applications of electromagnetic switches in Ghanaian homes, vehicles, industry and power distribution.
Explain the advantage of using an electromagnetic switch (such as a relay) to control a high-current circuit with a low-current circuit.

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Curriculum details

Strand: Electric Field, Magnetic Field and Electronics (Strand 3)
Sub-strand: Electromagnetism (3.2)
Content standard: 2.3.2.CS.2 - Demonstrate knowledge and understanding of the forces set up between parallel current-carrying conductors in a uniform magnetic field and applications. 2.3.2.LO.2 Demonstrate the repulsive and attractive forces between parallel current-carrying conductors in a magnetic field.
Indicator: 2.3.2.LI.4 - Describe the electromagnetic switches and applications.
Suggested placement: Semester 2, Week 9 (Week 29 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: NaCCA curriculum document, p. 128

Exemplars (from the NaCCA curriculum)

Experiential Learning: Learner draws and explain the construction and working principles of electromagnetic switches and their applications.
Recognise diverse talents and perspectives.
Assessment (2.3.2.AS.4). The document marks these depth-of-knowledge levels for this indicator: Level 1 Recall; Level 2 Skills of conceptual understanding.
Teaching and Learning Resources:
- Audio visuals
- Internet
- Projectors
- YouTube
- Interactive virtual laboratory