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 the factors on which the conductivity of a semiconductor depends, we can break down the problem into several steps:

### Step-by-Step Solution:

1. **Understanding Conductivity**:
- Conductivity (σ) is defined as the ability of a material to conduct electric current. It is the reciprocal of resistivity (ρ), which is a measure of how strongly a material opposes the flow of electric current.
- The relationship is given by the formula:
\[ \sigma = \frac{1}{\rho} \]

2. **Identifying Factors Affecting Resistivity**:
- Resistivity is influenced by several factors, including:
- The nature of the material (type of atoms present).
- The type of bonds formed between atoms.
- Temperature.
- Impurities and defects in the material.

3. **Considering Size and Shape**:
- Resistivity is an intensive property, meaning it does not depend on the size or shape of the material. Therefore, factors like the size of the atom or the overall dimensions of the semiconductor do not directly affect conductivity.

4. **Evaluating the Options**:
- **Size of Atom**: Incorrect, as resistivity does not depend on the size of the atom.
- **Size and Type of Motion**: This is somewhat ambiguous but generally incorrect in the context of conductivity, as it does not directly relate to the intrinsic properties affecting conductivity.
- **Type of Bonds**: Correct, as the type of bonds (ionic, covalent, metallic) influences how easily electrons can move through the material.
- **Nature of Atom**: Correct, as the specific elements and their electronic configurations play a significant role in determining conductivity.

5. **Conclusion**:
- Based on the above analysis, the conductivity of a semiconductor depends on:
- The type of bonds (Option 3).
- The nature of the atoms (Option 2).

Thus, the correct answer is that the conductivity of a semiconductor depends on the type of bonds and the nature of the atoms.

### Final Answer:
The conductivity of a semiconductor depends on the nature of the atoms and the type of bonds.

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