Invar, an alloy of Fe and Ni is used in watches and meter scale, its characteristic property is

Options

A. Small coefficient of expansion
B. Resistance to corrosion
C. Hardness and elasticity
D. Magnetic nature

Answer

**Step-by-Step Solution:**

1. **Understanding Invar**: Invar is an alloy primarily composed of iron (Fe) and nickel (Ni). It is known for its unique properties that make it suitable for specific applications.

2. **Applications of Invar**: This alloy is commonly used in precision instruments such as watches and meter scales. The reason for its use in these applications is due to its stability and resistance to changes in temperature.

3. **Characteristic Property**: One of the most notable characteristic properties of Invar is its low coefficient of thermal expansion. This means that Invar does not expand or contract significantly with temperature changes, which is crucial for maintaining accuracy in timekeeping and measurement.

4. **Additional Properties**: Besides its low coefficient of thermal expansion, Invar also exhibits other important properties:
- **Corrosion Resistance**: It can withstand environmental factors without degrading.
- **Elasticity and Hardness**: It has good mechanical strength, making it durable.
- **Magnetic Nature**: Invar retains magnetic properties, which can be beneficial in certain applications.

5. **Conclusion**: The characteristic property of Invar that stands out is its low coefficient of thermal expansion, making it ideal for precision instruments.

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