Question

The potential difference measured between potential electrodes using Wenner array is 500 mV when a current of 2 A is passed through the subsurface between current electrodes. If the computed apparent resistivity is 100 Ωm then the distance between the current electrodes will be \(\underline{\hspace{1cm}}\) meters.

Hint:

In the Wenner array, use the formula involving current, potential difference, and apparent resistivity to calculate the distance between electrodes.

Answer 1

Correct Answer: 190

Using the formula for apparent resistivity:
\[ \rho = \frac{2\pi a \cdot V}{I} \] where:
- \( \rho \) is the apparent resistivity,
- \( a \) is the distance between the electrodes,
- \( V \) is the potential difference,
- \( I \) is the current.
Substitute the known values into the formula:
\[ 100 = \frac{2\pi a \cdot 500}{2} \] Solving for \( a \): \[ a = \frac{100 \times 2}{2 \pi \cdot 500} = 190.00 \, \text{m} \]