# What is the expression used to calculate the cell constant G'?

The expression used to calculate the cell constant G’ is G’ = I/A

R = ρ 1/A = 1/kA

• l/A is called the cell constant denoted by the symbol, G’.
• The cell constant depends on the distance between the electrodes (l) and their area of cross-section (A).
• It is determined by measuring the resistance of the cell containing a solution of known conductivity.
• The cell constant is usually determined by measuring the cell’s resistance containing a solution whose conductivity is already known.
• For this purpose, we generally use KCl solutions whose conductivity is known accurately at various concentrations and different temperatures.

G’ = 1/A = Rk