1. What is Conductivity to Resistivity Conversion?

The conversion between conductivity (σ) and resistivity (ρ) is a fundamental relationship in material science, particularly for water quality assessment. Resistivity is the reciprocal of conductivity, representing how strongly a material opposes the flow of electric current.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( \rho \) — Resistivity in ohm-meters (Ω·m)
• \( \sigma \) — Conductivity in siemens per meter (S/m)

Explanation: Pure water has very low conductivity (high resistivity), while dissolved ions increase conductivity (decrease resistivity).

3. Importance of Resistivity Calculation

Details: Water resistivity is crucial for assessing purity in applications like semiconductor manufacturing, pharmaceutical production, and laboratory water systems.

4. Using the Calculator

Tips: Enter conductivity in S/m (1 µS/cm = 0.0001 S/m). The value must be greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the resistivity of ultra-pure water?
A: Ultra-pure water at 25°C has resistivity of about 18.2 MΩ·cm (0.000000055 S/cm conductivity).

Q2: How does temperature affect resistivity?
A: Water resistivity decreases with increasing temperature as ionic mobility increases.

Q3: What are typical conductivity values for drinking water?
A: Drinking water typically ranges from 50-1500 µS/cm (0.005-0.15 S/m).

Q4: Why measure resistivity instead of conductivity?
A: Resistivity is preferred for high purity water where conductivity values become very small.

Q5: What units are used for resistivity?
A: The SI unit is ohm-meter (Ω·m), but megohm-centimeter (MΩ·cm) is commonly used for pure water.