Alternating Current · SHS3 Physics

Lesson notes

Learning Objectives

Indicator: 3.3.2.LI.1 - Describe a.c. circuit connections using resistors, inductors, capacitors in series.

By the end of the lesson, learners can:

Draw a labelled diagram of a series a.c. circuit containing a resistor, an inductor and a capacitor connected to an a.c. source.
State the relationship between the applied voltage, current and the component voltages (V_S, V_R, V_L, V_C) in a series RLC circuit using the phasor approach.
Explain why the voltages across the inductor and capacitor oppose each other in a series RLC circuit.
Distinguish between the behaviour of a resistor, an inductor and a capacitor when connected in series to an a.c. source, using graphs of current and voltage against time.
Apply the equation Z² = R² + (X_L - X_C)² to determine whether a series RLC circuit is inductive, capacitive or resistive in nature.

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Curriculum details

Strand: Electric Field, Magnetic Field and Electronics (Strand 3)
Sub-strand: Alternating Current (3.2)
Content standard: 3.3.2.CS.2 - Explain the a.c series connected circuit 3.3.2.LO.2 Illustrate and describe the behaviour of alternating current
Indicator: 3.3.2.LI.1 - Describe a.c. circuit connections using resistors, inductors, capacitors in series.
Suggested placement: Semester 2, Week 5 (Week 25 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.179: the document prints this learning indicator code as 3.3.2.LI.3
exemplars - p.179: the document prints this assessment code as 3.3.2.AS.3 beside learning indicator 3.3.2.LI.1
Curriculum reference: NaCCA curriculum document, p. 179

Exemplars (from the NaCCA curriculum)

Experiential learning:
- Let learners watch videos on direct and alternating current to see how the current changes with time.
- Guide learners to use appropriate equations to establish equations for pure capacitive, pure inductive and pure resistive circuits.
- Let learners use sketched graphs to explain the behaviour of a.c in capacitor, inductor and resistor.
Encourage diverse perspectives and contributions.
Assessment (3.3.2.AS.3). The document marks these depth-of-knowledge levels for this indicator: Level 3 Strategic reasoning.
Teaching and Learning Resources:
- Audio-visuals,
- Internet
- Projectors
- YouTube
- Interactive
- Reference virtual laboratory books