The unit of electrical conductivity is

Options

A. `ohm-m^-2`
B. `ohmxxm`
C. `ohm^-1,m^-1`
D. none of these

Explanation

To determine the unit of electrical conductivity, we can start from the relationship between resistance, length, area, and conductivity.

### Step-by-Step Solution:

1. **Understanding the Formula**:
The relationship between resistance (R), length (L), area (A), and electrical conductivity (σ) is given by the formula:
\[ R = \frac{L}{σ \cdot A} \]
Rearranging this gives us:
\[ σ = \frac{L}{R \cdot A} \]

2. **Identifying Units**:
- The unit of length (L) is meters (m).
- The unit of resistance (R) is ohms (Ω).
- The unit of area (A) is square meters (m²).

3. **Substituting Units into the Formula**:
Substituting the units into the equation for conductivity:
\[ σ = \frac{\text{meters (m)}}{\text{ohms (Ω)} \cdot \text{meters}^2 (m^2)} \]

4. **Simplifying the Units**:
This can be simplified as follows:
\[ σ = \frac{m}{Ω \cdot m^2} = \frac{1}{Ω \cdot m} \]

5. **Final Unit of Electrical Conductivity**:
Therefore, the unit of electrical conductivity (σ) is:
\[ σ = \frac{1}{Ω \cdot m} \]

### Conclusion:
The unit of electrical conductivity is \( \text{S/m} \) (Siemens per meter), which is equivalent to \( \frac{1}{Ω \cdot m} \).