Question

The electrical resistance of a column of $0.04\, M\, NaOH$ solution of diameter $1.2\, cm$ and length $50\, cm$ is $5.55 \times 10^{3}$ ohm, the resistivity of the column would be

• A. $125.58\, ohm\, cm$
• B. $120.58\, ohm\, cm$
• C. $102.47\, ohm\, cm$
• D. $12.547\, ohm\, cm$

Answer 1

Answer: (A)

We know, $R =\rho \times \frac{l}{a}$ i .e $\rho =\frac{R \times a}{l}$
$a =\pi r^{2} =\pi \times \left(\frac{d}{2}\right)^{2} =\frac{22}{7} \times 0.36$
$\therefore \rho = 5.55 \times10^{3} \times \frac{22}{7} \times 0.36 \times \frac{1}{50}$
$= 125.58\,ohm\, cm$