Final answer:
To increase the resistance of a metal conductor, one can change its length, cross-sectional area, temperature, or material properties that affect electron flow. Copper is commonly used for electrical wiring due to its excellent conductivity and cost-effectiveness compared to silver.
Step-by-step explanation:
The electrical resistance of a metal conductor can be altered by changing variables that affect the flow of electrons through the conductor. On a microscopic level, electrons collide with the atoms of the metal as they move. This collision causes resistance as it transfers kinetic energy from the electrons to the metal atoms, which manifests itself as heat. Notably, when you touch a cellphone charger and feel its warmth, you're directly sensing the heat produced by resistance in the charger's circuits.
Since metals are typically used as electrical conductors due to their properties, including high electrical and thermal conductivity, altering these properties can increase the resistance of the conductor. For instance, making the metal conductor longer, thinner, hotter, or using a material with a higher innate electrical resistivity (like switching from copper to stainless steel) can increase its resistance.
Furthermore, copper is widely used in electrical wiring because it is a good conductor of electricity, and while silver is even better, it is not commonly used due to its high cost. Increasing a conductor's resistance might not always be desirable, especially for the efficient transmission of electrical power where reduced resistance is preferred to lessen energy losses.