🔍 Key Concepts

• Ohm's Law and the relationship between resistance, voltage, and current • The basic resistance formula for a conductor: dependence on length and cross‑sectional area • How temperature and material purity generally affect resistance in metals

💭 Think About

• Think about what happens to electron flow when a wire gets longer versus when it gets thicker. • Consider whether heating a metal usually makes electrons move more easily or less easily. • Ask yourself how having more impurities (less pure metal) changes the ease with which electrons can move through the wire.

✅ Before You Answer

• Write the resistance formula for a wire and identify which variables, when increased, make R go down. • Recall whether increasing temperature of most metals increases or decreases resistivity. • Think about whether a higher percent metallic purity means more or fewer scattering points for electrons in the metal.