a) Conductors

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

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

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

• larger number density = stronger the conductivity

insulator = weak electrical conductor

• number density = close to zero

semiconductor = moderate electrical conductor

• number density = around 10¹⁸m^-3

conductor = 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