← Physics syllabus

EnglandPhysics

Topic 5: Light and the electromagnetic spectrum

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

Why do objects appear coloured, and what does a colour filter do?

Colour and filters: how the colour of an opaque object depends on the wavelengths it reflects and absorbs, and how a colour filter transmits some colours and absorbs others.
A focused answer to Edexcel GCSE Physics 5.3 (separate physics), covering why opaque objects appear a particular colour through reflection and absorption of different wavelengths, why objects look black or white, and how colour filters transmit and absorb light.
8 min answer →

How does the nature of a surface affect the infrared radiation it emits and absorbs?

Infrared radiation and surfaces (core practical): how surface colour and texture affect the emission and absorption of infrared radiation, and the link to all objects emitting radiation.
A focused answer to Edexcel GCSE Physics 5.19 core practical (separate physics), covering how the nature of a surface affects the infrared radiation it emits and absorbs, that all objects emit and absorb infrared, the Leslie cube method, and the everyday consequences.
9 min answer →

What are the laws of reflection, and when does total internal reflection occur?

Reflection and total internal reflection: the law of reflection, specular versus diffuse reflection, the critical angle, and the conditions for total internal reflection.
A focused answer to Edexcel GCSE Physics 5.1 and 5.2 (separate physics), covering the law of reflection, the difference between specular and diffuse reflection, the critical angle, the conditions for total internal reflection, and its uses in optical fibres and prisms.
9 min answer →

How do converging and diverging lenses form images, and what is the power of a lens?

Refraction and lenses: refraction in a glass block (core practical), converging and diverging lenses, real and virtual images, and the power of a lens linked to focal length.
A focused answer to Edexcel GCSE Physics 5.4 to 5.6 and 5.9 (separate physics), covering refraction in a glass block (core practical), how converging and diverging lenses refract light, real and virtual images, ray diagrams, and the power of a lens linked to its focal length and shape.
10 min answer →

What is the electromagnetic spectrum, and how are its groups ordered?

The electromagnetic spectrum: the seven groups in order, the shared properties of EM waves, and the trends in wavelength, frequency and energy across the spectrum.
A focused answer to Edexcel GCSE Physics 5.7 to 5.13, covering the seven groups of the electromagnetic spectrum in order, the shared properties of electromagnetic waves, the trends in wavelength, frequency and energy, and the limited range our eyes can detect.
9 min answer →

What are the everyday uses and dangers of each part of the electromagnetic spectrum?

Uses and dangers of EM waves: the practical uses of each group, the harm high-frequency waves can cause to cells, and how the use links to the wave's properties.
A focused answer to Edexcel GCSE Physics on the uses and dangers of electromagnetic waves, covering the uses of radio, microwave, infrared, visible, ultraviolet, X-ray and gamma radiation, the harm caused by high-frequency waves, and how each use links to the wave's properties.
9 min answer →