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 2 of 2

Page 02

Total internal reflection

state

Try it yourself

Which statement gives the meaning of the critical angle?

state: choose the short, clear answer.

Choose one answera.The angle between the ray and the surface, inside the medium, when no light gets out.b.The angle of incidence, in the air, at which light stops getting into the medium.c.The angle of incidence, inside the medium, at which all of the light is reflected.d.The angle of incidence, inside the medium, at which the angle of refraction is 90°.

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Scope and sources

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

The normal, the angle of incidence and the angle of refraction (3.2.2.1); refraction by a rectangular and a semicircular glass block (3.2.2.2); the passage of light through a transparent material, at a boundary between two mediums (3.2.2.3); the critical angle (3.2.2.4); internal reflection and total internal reflection, with experimental and everyday examples (3.2.2.5); Supplement: refractive index as the ratio of the speeds of light (3.2.2.6), n = sin i ÷ sin r (3.2.2.7), n = 1 ÷ sin c (3.2.2.8) and optical fibres, particularly in telecommunications (3.2.2.9). Refraction of water waves is in Waves in a ripple tank, lenses in Lenses and images, and dispersion in Light and the electromagnetic spectrum.

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

Official Cambridge syllabus