The relation and units of cell constant are, respectively,

cell constant = $l/A$; units: $cm^{-1}$

The correct answer is Option (1) → cell constant = $l/A$; units: $cm^{-1}$

The cell constant in conductance measurements is defined as the ratio of the distance between the electrodes (l) to the area of cross-section (A).

$\text{Cell constant} = \frac{l}{A}$

Since

• $l$ is in cm
• $A$ is in cm²

the unit of cell constant is: $\text{cm}^{-1}$