Question

A conductivity cell shows resistance of 600 ohm. If conductivity of 0.01 M KCl is $0.0015\ \Omega^{-1}\ \text{cm}^{-1}$, what is cell constant?

• A. $0.60\ \text{cm}^{-1}$
• B. $0.45\ \text{cm}^{-1}$
• C. $0.90\ \text{cm}^{-1}$
• D. $0.75\ \text{cm}^{-1}$

Hint:

Cell constant is simply $\text{Conductivity} \times \text{Resistance}$. Multiplying $0.0015$ by 100 gives $0.15$, then multiplying $0.15$ by 6 yields $0.90$ instantly. Always watch out for simple decimal shift shortcuts!

Answer 1

The Correct Option is C

Step 1: Recall the link.
Conductivity equals conductance times the cell constant, and conductance is $1/R$. So cell constant $= k \times R$.

Step 2: Put in the values.
\[ G^* = 0.0015 \times 600 \]

Step 3: Compute.
That gives $0.90$ cm$^{-1}$.
\[ \boxed{0.90\ \text{cm}^{-1},\ \text{option 3}} \]