Electrodynamics — Grade 12 Past Paper Questions

DC generator analysis involving identification of components ensuring unidirectional current output, voltage characteristics, and energy dissipation calculations in connected electrical devices.

AC generator connected to a kettle, requiring analysis of pole polarity, methods to increase output, and calculations involving root mean square voltage and current.

Analysis of generator output using current-time graphs to determine generator type, frequency, and RMS current values, with comparison before and after operational modification.

AC generator with horizontal coil position analysis connected to an electrical device, involving resistance calculation and energy consumption using RMS voltage and current.

Sketch the output voltage versus time graph for an AC generator when the coil rotation speed is doubled, covering a 0.1-second time interval.

An AC generator with a rotating coil connected to a 25 Ω resistor. Identify the slip-ring component distinguishing it from DC generators, determine induced current direction, define and calculate RMS voltage and current, and find average power dissipated.

AC generator with a clockwise rotating coil connected to an external resistor. Determine current direction in the circuit, state energy transformation, calculate root mean square voltage and current values, find maximum induced current, and sketch current versus time for two complete rotations.

AC generator with coil at various positions. Explain electromagnetic induction and alternating emf production, identify maximum emf positions, sketch an emf-time graph labeling positions, calculate RMS current through a 100 Ω resistor, and describe conversion to DC operation.

Determine which ammeter shows the lowest reading in a parallel resistor circuit, and identify whether an illustrated machine with poles and rotating coil is a DC motor, AC motor, DC generator, or AC generator.

Multiple-choice questions on DC motor rotation direction changes through magnetic field alterations and relationships between atomic energy transitions and spectral line types.

Multiple-choice questions on energy conversion in electrical machines and relationships between electron energy transitions and emission or absorption spectral line characteristics.

Identify which voltmeter readings produce specific voltage-current graphs in a battery circuit with internal resistance, and explain how a split-ring commutator ensures continuous motor rotation by managing current direction.

Predict how ammeter and voltmeter readings respond when a switch opens in a circuit with negligible internal resistance, and identify which factors increase the magnitude of induced emf in an AC generator.