Question

The cell constant of a conductivity cell is

• A. $\dfrac{l}{A}$
• B. $\dfrac{A}{l}$
• C. $l \times A$
• D. $\dfrac{R}{A}$

Hint:

Large electrode area or small spacing $\Rightarrow$ smaller cell constant (more conductive cell).

Answer 1

The Correct Option is A

Step 1: Definition.
Cell constant ($G^*$) relates conductance to conductivity: $\kappa = G^* \cdot G$, where $G$ is conductance.
Step 2: Geometry dependence.
For parallel-plate electrodes, $G^*=\dfrac{l}{A}$, with $l$ = distance between electrodes and $A$ = area of electrodes.
Step 3: Conclusion.
Hence, the cell constant is $\dfrac{l{A}$}.