# Electrodynamics

Formula

Formula

Formula

## Long coil (magnetic field, number of turns, current)

Exercise with solution
Level 2 (suitable for students)

## Charge in a thundercloud

The exercise teaches you how to calculate the charge of a thundercloud using the capacitance and E-field in the plate capacitor.

Exercise with solution
Level 2 (suitable for students)

## Create a plate capacitor with a certain capacitance

In this exercise (with solution) you have to calculate the distance between the capacitor plates for a given capacitance and and than use relative permittivity.

Derivation
Level 4 (for very advanced students)

## Self-inductance of two current-carrying wires

Derive the self-inductance and magnetic flux of two parallel current carrying conductors with opposite currents.

Lesson
Level 2 (suitable for students)

## Lorentz Force: How to Determine its Direction and Understand Formula

Learn how Lorentz force (magnetic force) deflects a moving charge (electron) in the magnetic field and how you can determine the direction of the deflection.

Video
Level 1 (suitable for all)

## Electric Current explained simply in 7 minutes!

In this video you will learn the basics of the electric current, i.e. the definition, its physical meaning and unit.⠀

Content of the video
1. [00:00] Electric charges
2. [01:50] What causes the electric current?
3. [03:21] Formula + unit of electric current
4. [05:22] Is one ampere a large current?
5. [06:23] Summary