Regarding a semiconductor which one of the following statements is wrong?

Options

A. there are no free electron 0 K
B. there are no free electrons at room temperature
C. the number of free electrons increases with rise of temeparature
D. the charge carriers are electrons and holes.

Answer

To determine which statement regarding semiconductors is wrong, we need to analyze each statement provided in the question. Here’s the step-by-step solution:

### Step 1: Understand the properties of semiconductors
Semiconductors are materials that have electrical conductivity between that of conductors and insulators. They can conduct electricity under certain conditions and are crucial in electronic devices.

### Step 2: Analyze the statements
1. **Statement A**: "There are no free electrons at 0 Kelvin."
- At absolute zero (0 Kelvin), all thermal energy is removed, and electrons occupy the lowest energy states. Thus, there are no free electrons available for conduction. This statement is true.

2. **Statement B**: "There are no free electrons at room temperature."
- At room temperature, semiconductors do have some free electrons due to thermal excitation. This statement is false.

3. **Statement C**: "The number of free electrons increases with rise in temperature."
- As temperature increases, more electrons gain enough energy to jump from the valence band to the conduction band, resulting in an increase in the number of free electrons. This statement is true.

4. **Statement D**: "The charge carriers are holes and electrons."
- In semiconductors, charge carriers are indeed electrons (negative charge) and holes (positive charge). This statement is true.

### Step 3: Identify the wrong statement
From the analysis, Statement B is incorrect because it asserts that there are no free electrons at room temperature, which is not true.

### Conclusion
The wrong statement regarding semiconductors is **Statement B**.

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