From energy levels to laser light
From energy levels to laser light

A photon is a discrete packet of electromagnetic radiation, and laser action depends on particles having allowed energy levels. When a particle changes level, it absorbs or emits a photon whose energy matches the gap:
Step-by-step lessons covering Eduqas A Level Physics Lasers for A Level Physics. Each lesson works through exam-style questions in Component 1, Component 2 and Component 3 format. Physics is one of the most mathematically demanding A Levels -- a minimum of 40% of the marks require maths skills at Level 2 (GCSE) standard or above, so build calculation and graph-handling fluency alongside the conceptual content from the start.