Resistivity and Superconductivity

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.
• ρ=RA/l

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