Electrical resistance. What is the reason for the resistance? Resistance units.

Electrical resistance is an obstacle on the part of a conductor to the electric current passing through it. When electrons pass through the crystal lattice, they collide with the conductor particles, kinetic energy is transferred to them, so the conductor heats up. Resistance is measured in ohms or multiple units – milliohms, microohms, megaohms, gigaohms, etc. Resistance depends on the conductor material, cross-sectional area and length. The same current in a conductor with a higher resistance will cause more heating than in a conductor with less resistance.