Paper 2 at a glance
- Paper 2 carries 100 marks in total
"Define" items from this chapter
One precise sentence each; the unit is part of the definition where there is one.
- Thermionic emission, The release of electrons from the surface of a heated metal when it is given enough thermal energy.
- Cathode ray, A stream of fast-moving electrons emitted from a cathode and travelling towards the anode in a vacuum tube.
- Semiconductor, A material whose electrical conductivity lies between that of a conductor and an insulator, such as silicon.
- Doping, The process of adding a small, controlled amount of impurity to a pure semiconductor to change its electrical properties.
- n-type semiconductor, A semiconductor doped so that free electrons are the majority charge carriers.
- p-type semiconductor, A semiconductor doped so that positive holes are the majority charge carriers.
"Explain" items from this chapter
Give the physics reason, not a description. Model answers in one breath:
- What a semiconductor diode does, A diode lets current flow through it in one direction only. This one-way behaviour is used to turn alternating current into direct current, called rectification.
- How a transistor acts as a switch, A small current into the base of a transistor lets a much larger current flow through the main circuit. Removing the small current switches the large one off, so the transistor works as an electronic switch.
- What doping does to a semiconductor, Adding a tiny amount of impurity to pure silicon greatly increases its ability to conduct. Depending on the impurity, it forms n-type or p-type material, the building blocks of diodes and transistors.
Diagram and description items
This chapter carries no formula, so Paper 2 marks come from labelled diagrams, descriptions of procedures and precise definitions. Practise drawing each diagram from memory with every label.
- Semiconductor diode, A component made from a p-n junction that allows current to flow in one direction only.
- Rectification, The process of converting alternating current into direct current, usually using diodes.
- Transistor, A semiconductor device with three terminals used to amplify signals or to act as an electronic switch.
- Light-emitting diode (LED), A semiconductor diode that emits light when a current flows through it in the forward direction.
- Electron, A stable subatomic particle carrying a negative electric charge, found orbiting the nucleus of an atom.
Other command words
- Describe, say what happens, in order, with the observable evidence; keep "why" for an explain mark.
- Sketch, axes labelled with units, the shape that matters (curve vs straight line, intercept, origin), no plotted numbers needed.
Where the marks are in this chapter
The 3 content standards of Electronics can each be asked as a definition, an explanation, a calculation or a diagram. We do not predict which will appear, prepare all of them.
A three-step answer routine
- Decide the answer type first: definition, reason, number or drawing.
- For numbers, write the rearranged formula on its own line before substituting.
- Check the magnitude is sensible for the situation before moving on.
Exam tip
Units on every calculation line; no formula is provided in the SPM Physics papers.
More Electronics resources
Source: DSKP KSSM Physics Form 4 and 5 (Versi English), Sijil Pelajaran Malaysia: Format Pentaksiran mulai 2021, Fizik (4531) (Bahagian Pembangunan Kurikulum (BPK), KPM)
Written by the spmphysics.com.my editorial team.· Updated 5 Sept 2026