For those looking for good free physics courses online, my best recommendation is Leonard Susskind’s lectures. Susskind’s lectures on a variety of physics topics can be found on YouTube as a part of Stanford University’s open lectures. Besides being a renowned theoretical physicists, Susskind is also known for his easy-to-follow lectures. The problem, ironically, is that there are so many lectures, it’s hard to find what you looking for. Fortunately, there is a great website, which offers all the most important lectures in different formats.
The Theoretical Minimum website includes 6 main lecture courses, plus additional 9 courses on advanced topics. The archive section contains older versions of the core courses. Here’s the list of topics covered in core courses:
1. Classical Mechanics (Newton’s laws, Lagrangian, electromagnetic fields, symmetries and conversations)
2. Quantum Mechanics (vector spaces, Schrodinger’s equation, entanglement, Fourier analysis, particles)
3. Special Relativity and Electrodynamics (Lorentz transformations, velocity addition, classical field theory, Maxwell equations)
4. General Relativity (equivalence principle, tensors, curvature, geodesics, black holes, field equations, gravity waves)
5. Cosmology (expanding universe, curvature, cosmic thermodynamics, baryogenesis, inflation, quantum fluctuations)
6. Statistical physics (entropy, temperature, Boltzmann distribution, reversibility, liquid-gas transition)
For more high-quality lectures visit Stanford University YouTube channel.