Electromagnetic Induction… · SHS3 Physics

Lesson notes

Learning Objectives

Indicator: 3.3.3.LI.2 - Discuss the factors that affect the transmission of power and efficiency of a transformer and ways of improving its efficiency.

By the end of the lesson, learners can:

Explain how a transformer affects the relationship between potential difference and current in an alternating current circuit, using the power conservation principle.
State at least four factors that reduce the efficiency of a transformer and explain the physical mechanism behind each.
Describe practical methods used to minimise each type of power loss in a transformer.
Calculate the efficiency of a transformer given input and output power values, and express it as a percentage.
Discuss why high voltage, low current transmission is preferred for transmitting electrical power over long distances, using Ghana’s national grid as a reference.

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Curriculum details

Strand: Electric Field, Magnetic Field and Electronics (Strand 3)
Sub-strand: Electromagnetic Induction & Applications (3.3)
Content standard: 3.3.3.CS.3 - Demonstrate knowledge and understanding of the principles of operation of transformers. 3.3.3.LO.3 Describe the structure, principle of operation and applications of a transformer.
Indicator: 3.3.3.LI.2 - Discuss the factors that affect the transmission of power and efficiency of a transformer and ways of improving its efficiency.
Suggested placement: Semester 2, Week 11 (Week 31 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.
Source document note: The official curriculum document has a fault in this entry, so the curriculum text above is transcribed exactly as printed:

indicator text - p.188: the document prints this learning indicator code as 3.3.3.LI.1.2
exemplars - p.188: the document prints this assessment code as 3.3.3.AS.1.2
Curriculum reference: NaCCA curriculum document, p. 188

Exemplars (from the NaCCA curriculum)

Talk for learning:
- Describe the effect of transformers on the relationship between the potential difference and current of an electrical signal
- Discuss the factors that affect transformer performance and efficiency.
- Describe how these factors can be minimised
Foster an inclusive and respectful classroom culture and address bias in teaching materials and examples.
Assessment (3.3.3.AS.2). The document marks these depth-of-knowledge levels for this indicator: Level 1 Recall; Level 2 Skills of conceptual understanding; Level 4 Extended critical thinking and reasoning.
Teaching and Learning Resources:
- Audio-visuals
- Internet
- Projectors
- YouTube
- Interactive virtual laboratory
- Practical
- Reference laboratory books setup