To see the concept of electrical resistance, let's get back to hydraulics again.
We take two vessels containing water at different levels and communicating through a section.
The flow of flow water, its speed depends on the size of the section.
In the A strong> case, the link section is bigger and allows a greater passage of water and less resistance.
Similarly in the electrical circuit with potential difference (the difference in level in the two vessels) the connection section will create greater or lesser resistance to its characteristics.
Size and measurement unit
Resistance is commonly referred to as the letter R and its unit of measurement is the ohm whose symbol is the Greek omega Ω