a) Conductors

c) distinction between conductors, semiconductors, and insulators in terms of n

number density = the number of free electrons per unit volume in a material

• number density (m^-3) = number of free electrons / volume (m³)

• the larger number density, the stronger the conductivity

insulator = a weak electrical conductor

• number density = close to zero

semiconductor = a moderate electrical conductor

• number density = around 10¹⁸m^-3

conductor = a strong electrical conductor

• number density = around 10²⁸m^-3

to increase the conductivity of a conductor

• the electrons would have to move faster

  • by increasing the potential difference

  • by decreasing the resistance