===============
Chapter 4
===============

.. raw:: html

   <iframe width="560" height="315" src="https://www.youtube.com/embed/P3ypbMpLHYA" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>


Lecture notes :download:`pdf <files/Phys343-C4.pdf>`