Three things determine resistance:
- Length: The longer the wire the more difficult it is for current to flow.
- Area: The wider the wire the easier it will be for electrons to get through it.
- Resistivity: (depends on material). The structure may may it easy or difficult for charge to flow. It also depends on environmental factors such as temperature or light intensity.
- The resistivity of a material is defined as the resistance of 1m length with a 1m² cross-sectional area. It is measured in ohm-metres.