1 hour ago, MigL said:

How fast do [holes] 'travel' ?

As fast as the electrons can get out of their way! 😊

14 hours ago, Morto said:

I remember been taught at school that the electricity is a movement of electrons. Ok, it's nice and clear. But then I found out that the speed with which electrons are moving in a wire is millimiters per second. It doesn't make sense to me. So what is electricity if it's not a movement of electrons and what is the speed of it?

I would think you were actually taught rather more than

'electricity is a movement of electrons' 

Electricity is usually the general term for the phenomenon of several effects we lump together and call 'electricity'.

That would include 'static electricity' , electric current, ionic mobility and a whole host of other effects.

Which one are you particularly interested in ?

Thank you It is helpful information

Good reading filled with an overdose of links.  It will make you crazy or give you light.  Or both :

---> http://amasci.com/miscon/whatis.html

The electricity is an electromagmentic wave and the speed of electromagnetic waves always equal to 3×10^8 m/s that is the speed of light. Hence the electricity flows at the speed of light that is at 3×10^8 m/s.

The electricity is an electro magmentic wave and the speed of electromagnetic waves always equal to 3×10^8 m/s that is the speed of light. Hence the electricity flows at the speed of light that is at 3×10^8 m/s.

The electricity is an electromagmentic wave and the speed of electromagnetic waves always equal to 3×10^8 m/s that is the speed of light. Hence the electricity flows at the speed of light that is at 3×10^8 m/s.
 

1 hour ago, Tutoroot said:

The electricity is an electromagmentic wave and the speed of electromagnetic waves always equal to 3×10^8 m/s that is the speed of light. Hence the electricity flows at the speed of light that is at 3×10^8 m/s.
 

!

Moderator Note

One incorrect answer is enough. No need to repeat it.

(electricity is not an EM wave, and does not flow at c)