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I am Alexander Fufaev, physicist and owner of this website. Here you can find free, high-quality content about physics. Courses, exercises with solutions, questions and answers and much more!
Physics courses


A course is an ordered learning unit that will take you step by step through a comprehensive physics topic so that by the end you will have mastered it.

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Level 3 (for advanced students)

Hermite Operators Simply Explained

In this physics video you will learn what Hermitian operators and matrices are and what important properties they have.

Content of the video
  1. 00:00 Motivation: Real mean values
  2. 01:16 What are Hermitian operators?
  3. 02:16 What is a self-adjoint operator?
  4. 02:56 Notation of a Hermitian operator
  5. 03:20 Eigenvalues are real
  6. 04:27 Eigenvectors are orthogonal
  7. 05:56 Eigenvectors form a basis
  8. 06:37 What is a Hermite matrix?
  9. 07:19 Examples for (non) Hermitian matrices
Level 2 (suitable for students)

Lorentz force simply explained in 6 minutes!

In this video you will learn how to determine the direction of the Lorentz force using left/right hand rule and how this force is calculated and related to the centripetal force.

Content of the video
  1. 00:00 What is Lorentz force?
  2. 00:28 Moving charge perpendicular to the magnetic field
  3. 01:12 Determine Lorentz force direction
  4. 02:40 Lorentz force qvB-equation
  5. 04:12 Movement at an angle to the magnetic field
  6. 04:59 Lorentz and centripetal force
  7. 06:20 Determine velocity of the electron