Contents

Motion, forces and energy

Thermal physics

Waves

Electricity and magnetism

Magnets and magnetic fields
Static electricity and electric fieldsBeing prepared
Current and circuit diagramsBeing prepared
Voltage and resistanceBeing prepared
Series and parallel circuitsBeing prepared
Sensors and potential dividersBeing prepared
Electricity at homeBeing prepared
ElectromagnetsBeing prepared
The motor effectBeing prepared
Generators and inductionBeing prepared
Transformers and the gridBeing prepared

Nuclear physics

Inside the nucleusBeing prepared
Ionising radiation and safetyBeing prepared
Radioactive decay and half-lifeBeing prepared

Space physics

Earth, Sun and MoonBeing prepared
The Solar System and orbitsBeing prepared
Stars and their life cycleBeing prepared
The expanding UniverseBeing prepared

Part 1 of 2

Page 01

Emitting infrared

state

Try it yourself

Which statement about thermal radiation is correct?

state: choose the short, clear answer.

Choose one answera.Thermal radiation is infrared radiation, and all objects emit it; hotter objects emit more each second.b.Thermal radiation is infrared radiation, and only black objects emit it.c.Thermal radiation is visible light, so only objects that glow emit it.d.Thermal radiation is infrared radiation, and only objects hotter than their surroundings emit it.

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Cambridge IGCSE Physics 0625 · 2026–2028 v2 · Original learning materials.

Thermal radiation as infrared radiation, which all objects emit (2.3.3.1), and which needs no medium (2.3.3.2); the effect of surface colour (black or white) and texture (dull or shiny) on emitting, absorbing and reflecting infrared (2.3.3.3); Supplement: the energy balance of an object at constant temperature (2.3.3.4), and what happens when it receives energy faster or slower than it transfers energy away (2.3.3.5); the Earth’s temperature and the factors that control its balance of incoming and emitted radiation, such as greenhouse gases and ice (2.3.3.6); experiments to tell good and bad emitters (2.3.3.7) and absorbers (2.3.3.8) of infrared; how the rate of emission depends on surface temperature and surface area (2.3.3.9); applications where more than one transfer matters: a fire burning wood or coal and a radiator in a car (2.3.4.2), and also a vacuum flask. Conduction and convection are in Conduction and convection; the electromagnetic spectrum and wavelengths of infrared are in a later module.

Apparatus, amounts and times in the experiment are illustrative. Real practical work follows a teacher-approved safety method.

Official Cambridge syllabus