DrG-Physics · Inverse Square Law · SQA Higher Physics revision

Higher Physics on irradiance and the inverse square law of light. Five SQA-style questions fully worked. EXAM + STUDY editions included.

A focused single-topic revision companion on the Inverse Square Law of Irradiance for SQA Higher ‘Particles & Waves’ (the wave half — Volume II — Light). Covers irradiance, the I = P/(4πd²) relationship for point sources, and the standard SQA-described verifying experiment.

The DrG-Physics revision companion is not a worksheet. It is a structured exam-thinking guide — built around the way an SQA marker reads your script. Each worked solution leads with the relationship the examiner is looking for, substitutes cleanly, and evaluates with units. Every question carries a marker-aligned command-word tag (CALCULATE · 2 marks · STATE + JUSTIFY) so students learn what kind of answer earns each mark.

WHAT’S INSIDE
• Theory chapter on irradiance and the inverse-square geometry, with a diagram showing the area-with-distance scaling
• Five SQA-style questions covering basic irradiance from a small lamp, the verifying experiment with sample data, the Earth-Mercury solar-irradiance comparison, why a point source is required, and finding distance from irradiance
• Special focus on the ‘plot I against 1/d² (not d!)’ rule and the 4π factor that catches half the candidates
• Examiner’s Note after every question naming the typical pitfall
• Do/Don’t pair to reinforce SQA marking conventions

TWO EDITIONS · ONE DOWNLOAD
• EXAM Edition — clean, concise solutions for printing and exam-style practice
• STUDY Edition — same content plus ‘Why’ reasoning panels before each part

PART OF THE SERIES
One of four topics in ‘Particles & Waves Vol II — Light’. Try PW01 — Standard Model FREE to experience the approach.

Written and produced by Dr Godoy, GTCS-registered Physics teacher, Edinburgh.