For part 1, please visit:    • A Level Physics Revision: All of Wave...  
All of my revision videos:
   • A Level Physics Revision Videos  

Chapters:
00:00 Intro
00:15 Superposition
03:05 Coherence
03:56 Path Difference and Phase Difference
05:08 Constructive Interference Conditions
08:45 Destructive Interference Conditions
11:57 Practice Question

This is excellent A Level Physics revision for all exam boards including OCR A Level Physics, AQA A level Physics, Edexcel A Level Physics, CIA Cambridge International A Level Physics, Eduqas etc.