The resistivity of alloys is usually

Options

A. more than its constituents
B. less than its constituents
C. equal to its constituents
D. none of these

Explanation

To answer the question regarding the resistivity of alloys, we can break down the solution into several steps:

### Step-by-Step Solution:

1. **Understanding Resistivity**:
- Resistivity (ρ) is a property of materials that quantifies how strongly they resist the flow of electric current. It is influenced by the material's composition and structure.

2. **Properties of Alloys**:
- Alloys are mixtures of two or more metals (or a metal and a non-metal) that are designed to enhance certain properties compared to their individual components. These properties can include strength, corrosion resistance, and electrical resistivity.

3. **Resistivity of Alloys vs. Constituents**:
- Generally, the resistivity of an alloy is different from that of its individual components. The resistivity of an alloy is usually **greater** than that of its individual constituent metals. This is because the mixing of different metals disrupts the regular lattice structure, leading to increased scattering of charge carriers (electrons).

4. **Examples of Alloys**:
- For example, brass is an alloy made from copper and zinc. Copper has a lower resistivity compared to brass, indicating that the resistivity of the alloy (brass) is higher than that of its constituent (copper).

5. **Applications of High Resistivity**:
- Alloys with higher resistivity are often used in applications where a specific resistance is required, such as in heating elements. Higher resistivity allows for shorter lengths of material to achieve the desired resistance, which is beneficial in many electrical applications.

6. **Conclusion**:
- Based on the above points, we conclude that the resistivity of alloys is usually **more than** that of their constituents.

### Final Answer:
The resistivity of alloys is usually **more than** its constituents.

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