The conductivity of a semiconductor depends upon

Options

A. Size of the atom
B. The nature of atom
C. Types of bonds
D. Size and types of motion

Answer

To determine what the conductivity of a semiconductor depends upon, we can analyze the options provided step by step:

### Step 1: Understanding Conductivity and Resistivity
- **Conductivity (σ)** is defined as the ability of a material to conduct electric current, and it is inversely related to **resistivity (ρ)**. The relationship can be expressed as:
\[ \sigma = \frac{1}{\rho} \]
- Therefore, a lower resistivity means higher conductivity.

### Step 2: Evaluating the Options
1. **Option 1: Size of the Atom**
- The size of the atom does not significantly affect the conductivity of a semiconductor. Conductivity is more influenced by the availability of charge carriers rather than the atomic size.
- **Conclusion**: This option can be eliminated.

2. **Option 2: Nature of the Atom**
- The nature of the atom refers to the type of elements present in the semiconductor (e.g., silicon, germanium). Different atoms have different electronegativities and band gaps, which affect the number of charge carriers available for conduction.
- **Conclusion**: This option is likely to be correct.

3. **Option 3: Type of Bonds**
- The type of bonds (ionic, covalent, metallic) can influence the properties of materials, but in semiconductors, the conductivity is primarily influenced by the nature of the atoms and the band structure rather than just the bond type.
- **Conclusion**: This option can be eliminated.

4. **Option 4: Size and Types of Motion**
- This option is vague and does not directly correlate with the fundamental principles of semiconductor conductivity. While motion of charge carriers is important, the size aspect is not a primary factor.
- **Conclusion**: This option can be eliminated.

### Step 3: Final Conclusion
- After evaluating all the options, we conclude that the conductivity of a semiconductor primarily depends on the **nature of the atom**. Thus, the correct answer is:
- **Option 2: Nature of the Atom**

### Summary of the Solution
The conductivity of a semiconductor depends upon the nature of the atom, as it influences the availability of charge carriers and the band structure of the material.

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