Reciprocal of resistance is :

Options

A. Conductance
B. Voltage
C. Resistivity
D. Reactance

Explanation

To solve the question "Reciprocal of resistance is:", we need to understand the relationship between resistance and conductance.

### Step-by-Step Solution:

1. **Understanding Resistance**:
- Resistance (R) is a measure of the opposition to the flow of electric current in a conductor. It is measured in ohms (Ω).

2. **Reciprocal of Resistance**:
- The reciprocal of resistance is mathematically represented as \( \frac{1}{R} \).

3. **Definition of Conductance**:
- Conductance (G) is defined as the ability of a material to conduct electric current. It is the reciprocal of resistance.
- Mathematically, conductance is given by \( G = \frac{1}{R} \).
- Conductance is measured in siemens (S).

4. **Analyzing the Options**:
- The options provided are:
1. Conductance
2. Voltage
3. Resistivity
4. Reactance
- From our understanding, the reciprocal of resistance is conductance.

5. **Conclusion**:
- Therefore, the correct answer is option 1: Conductance.

### Final Answer:
The reciprocal of resistance is **Conductance**.

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