Which is the wrong statement in following sentence? A device in which P and N type semiconductors are used is more useful then a vacuum tube because-

Options

A. power is not necessary to heat the filament
B. it is more stable
C. very less heat is producted in it
D. its efficiency is high due to a high voltage drop across the junction.

Answer

To determine the wrong statement in the given sentence about the usefulness of devices using P and N type semiconductors compared to vacuum tubes, let's analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding the Context**:
- We are comparing devices that utilize P-N junctions (semiconductors) with vacuum tubes.
- We need to identify which statement about the advantages of semiconductors is incorrect.

2. **Statement Analysis**:
- **Statement 1**: "Power is not necessary to heat the filaments."
- **Analysis**: This statement is true. Semiconductors do not require filaments to operate, unlike vacuum tubes which need power to heat filaments.

- **Statement 2**: "It is more stable."
- **Analysis**: This statement is also true. P-N junctions are generally more stable than vacuum tubes, which can be sensitive to temperature and other conditions.

- **Statement 3**: "Very less heat is produced in it."
- **Analysis**: This statement is true. Semiconductors produce significantly less heat compared to vacuum tubes, which dissipate a lot of heat due to the filaments.

- **Statement 4**: "Its efficiency is high due to the high voltage drop across the junction."
- **Analysis**: This statement is incorrect. While semiconductors can be efficient, the efficiency is not primarily due to a high voltage drop across the junction. In fact, a high voltage drop can lead to power losses, and semiconductors are designed to operate efficiently at lower voltage drops.

3. **Conclusion**:
- The wrong statement is: "Its efficiency is high due to the high voltage drop across the junction."

### Final Answer:
The wrong statement is: "Its efficiency is high due to the high voltage drop across the junction."

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