# Quantum mechanics

Here you will learn the strange behavior of the microcosm: the quantization of energy, uncertainty principle, quantum tunnelling and so on. Enter the world of the building blocks of our universe.
Video
Level 2 (without higher mathematics)

## Photoelectric Effect and The Einstein Formula Simply Explained

Here you will learn what the photoelectric effect is, how it can be described with a Einstein formula + everything you need to know about it.

Content of the video
1. 00:00 What is the photoelectric effect?
2. 00:07 Experiment setup
3. 00:46 Photons
4. 01:58 Work function and threshold frequency
5. 03:48 Convert electron volts to joules and vice versa
6. 04:19 Kinetic energy of an electron
7. 04:50 Einstein formula
8. 05:36 Stopping (braking) voltage
9. 07:20 Energy frequency graph
Formula

## Wien's Displacement Law (Temperature, Wavelength)

Video
Level 3 (with higher mathematics)

## Hermitian 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
Video
Level 2 (without higher mathematics)

## De-Broglie Wavelength And The Wave-Like Matter

Here you will learn about de Broglie wavelength (matter wavelength), its derivation, an example and how de Broglie wavelength can be expressed with voltage.

Content of the video
1. [00:00] Wave-particle duality
2. [00:46] Derivation of the De Broglie wavelength
3. [02:40] Example
4. [03:35] De Broglie wavelength using voltage
Formula

## De Broglie wavelength (mass, velocity)

Lesson
Level 2 (without higher mathematics)

## De Broglie Wavelength of Matter Waves

Here you will learn about matter waves and how they are characterized by the de Broglie wavelength (matter wavelength).

Lesson
Level 2 (without higher mathematics)

## Photoelectric effect: How to understand the revolutionary experiment just like Einstein did

Here you will learn how the photoelectric effect is explained quantum mechanically, how the stopping voltage method works and everything else you need to know.