M

a) conductors

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

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

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

  • the greater number density, the stronger the conductor

insulator = a weak electrical conductor

  • number density = close to zero

semiconductor = a moderate electrical conductor

  • number density = around 10^18m^-3

conductor = a strong electrical conductor

  • number density = around 10^28m^-3

to increase the conductivity of a conductor

  • the electrons would have to move faster

    • by increasing the potential difference

    • by decreasing the resistance