Resistance is a measure of the resistance to the flow of current in a circuit. Resistance is measured in ohms and is represented by the Greek letter omega (Ω). Ohms are named after German physicist Georg Simon Ohm, who studied the relationship between voltage, current, and resistance.
The resistance of a long wire is greater than that of a short wire because the electrons collide with many ions as they pass. The relationship between resistance and wire length is proportional.
The current through a thin wire is greater than the current through a thick wire because the thin wire has fewer electrons to carry the current.
The relationship between the resistance and the area of a wire’s cross-section is inversely proportional.
What causes electric resistance?
An electric current flows when electrons move through a conductor, such as a metal wire.
The moving electrons can collide with the ions in the metal, causing them to move.
This makes it difficult for the current to flow and causes resistance.