GCSE Physics diagrams investigating coincidence of reflection and refraction of visible light rays at interface air-glass, air-water, air-transparent plastic like perspex IGCSE/GCSE Physics revision notes

GCSE level Physics exam revision notes on light and reflection

Visible light Part 4. The coincidence of reflection and refraction of visible light rays at an interface e.g. air-glass, air-water, air transparent plastic like Perspex

[Author © Dr Phil Brown PhD: Doc Brown's physics exam revision notes suitable for students of UK IGCSE & GCSE level physics courses, ~ US grades 9-10 physics [waves-light- page updated April 19th 2026 *]

email doc brown: comments? query? * [privacy & cookies policies & disclaimer] * ]SEARCH]

INDEX of physics optics notes on visible light rays involving reflection, refraction and diffraction

and Refraction of waves and scientific model

4. The coincidence of reflection and refraction of visible light rays at an interface

Ray analysis diagram for less dense to a more dense medium e.g. air => water, air => glass or air => transparent plastic (like Perspex).

Light ray passing through an interface from air into water (same for glass or plastic rectangular prisms)

When an incident ray of light hits a water or glass surface at the sort of angle illustrated, most of the light passes through the air-water interface and refracted, but a little is reflected.

Ray 1 is a correct 'fainter' reflected light ray (angle of incidence = angle of reflection).

Ray 2 is an incorrect reflected ray (angle i does not equal angle r).

Ray 3 is an incorrect refracted ray (bends away from the 'normal').

Ray 4 is a correct refracted ray (on entering a more dense medium the ray is bends towards the 'normal', angle of incidence > angle of refraction).

Ray analysis diagram for a more dense to a less dense medium e.g. glass => air, water => air, transparent plastic block (like Perspex) => air

Light ray passing through an interface from water (same for glass or plastic rectangular prisms) out into air.

In the diagram an incident ray of light hits a transparent surface at the sort of angle illustrated, most of the light passes through the air-water interface and refracted, but a little is reflected.

Ray 1 is an incorrect refracted ray (bends towards the 'normal')

Ray 2 is the correct refracted ray (on entering a less dense medium, the ray bends away from the 'normal', angle of incidence < angle of refraction).

Ray 3 is an incorrect reflected ray (angle i does not equal angle r).

Ray 4 is the 'fainter' but correct reflected ray (angle of incidence = angle of reflection).

ray diagram for reflection in a thick silvered surface plain mirror GCSE physics AQA Edexcel OCR Reflection in a silvered thick glass plane mirror

Rather more complex than you imagine, involving both reflection and refraction.

Ray line 1 represents an incident visible light ray in air.

Ray line 2 is the first refraction, bending towards the normal in a more dense medium (glass).

Ray line 3 is the reflected ray from the ray line 2 (angle of incidence = angle of reflection on the silvered surface).

Ray line 4 is the direct reflection of ray line 1 (no refraction involved).

Ray line 5 is the refraction of ray line 3 (refracted ray bends away from the 'normal' in a less dense medium).

INDEX notes: Visible light rays - reflection, refraction and diffraction

Information sources for Doc Brown's key points: IGCSE-GCSE physics are based on textbooks & syllabus-specifications for students taking the UK AQA, Edexcel, OCR 21st Century Science, OCR Gateway science suite, WJEC, CCEA and CIE GCSE physics 9-1 level science examinations

Keywords, phrases and learning objectives for the behaviour of visible light rays

Be able to describe and explain the coincidence of reflection and refraction of visible light rays at an air-glass interface, air-water interface and an air-transparent plastic interface like Perspex.

WHAT NEXT?

TOP of page

INDEX of physics optics notes on visible light rays involving reflection, refraction and diffraction

INDEX of all notes on waves, radiation, astronomy etc.

Revision notes on describing & explaining the coincidence of reflection & refraction at an air-glass or air-water interface based on the syllabus-specifications for students taking IGCSE/GCSE level physics examinations, summary revision notes and key points on describing & explaining the coincidence of reflection & refraction at an air-glass or air-water interface for students taking the AQA igcse/gcse physics notes on describing & explaining the coincidence of reflection & refraction at an air-glass or air-water interface, Edexcel gcse physics notes on describing & explaining the coincidence of reflection & refraction at an air-glass or air-water interface, OCR 21st century GCSE physics notes on describing & explaining the coincidence of reflection & refraction at an air-glass or air-water interface, OCR gateway GCSE physics notes on describing & explaining the coincidence of reflection & refraction at an air-glass or air-water interface, WJEC gcse physics notes on describing & explaining the coincidence of reflection & refraction at an air-glass or air-water interface, CCEA gcse physics notes on describing & explaining the coincidence of reflection & refraction at an air-glass or air-water interface for students taking CIE Cambridge igcse physics, exam revision notes on describing & explaining the coincidence of reflection & refraction at an air-glass or air-water interface, useful for US grade 9-10 physics courses, importance of measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface in GCSE level physics, What you need to know about measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface for GCSE level physics, Explaining the use of measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface knowledge in GCSE level physics, Examples of measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface explained when studying GCSE level physics, What is significant about measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface, describing the theory of measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface when studying GCSE level physics, revision notes for measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface in exams, online exam help for measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface, revision notes about measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface, what do I need to learn about measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface for by GCSE physics exam? help to understand the measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface topic in preparation for GCSE physics exam question, how to prepare for questions involving measuring angles of incidence & angles of reflection at a air-glass/Perspex or air-water interface in a GCSE physics examination?

SITEMAP Website content © Dr Phil Brown 2000+. All copyrights reserved on Doc Brown's physics revision notes, images, quizzes, worksheets etc. Copying of website material is NOT permitted. Exam revision summaries and references to GCSE science course specifications are unofficial.

INDEX notes: Visible light rays - reflection, refraction and diffraction