text: Resistance, , is proportional to the distance, , between the electrodes and is inversely proportional to the cross-sectional area of the sample,  (noted  on the Figure above). Writing  (rho) for the specific resistance, or resistivity.
  In practice the conductivity cell is calibrated by using solutions of known specific resistance, , so the individual quantities  and  need not be known precisely, but only their ratio. If the resistance of the calibration solution is , a cell-constant, defined as the ratio of  and  ( = ), is derived.
  The specific conductance (conductivity),  (kappa) is the reciprocal of the specific resistance.
  Conductivity is also temperature-dependent.
  Sometimes the conductance (reciprocical of the resistance) is denoted as  = . Then the specific conductance  (kappa) is: