Which of the following statements is incorrect about electrostatic precipitators ?

Options

A. ESP can remove over 99% particulate matter present in exhaust from a thermal power plant .
B. Collecting plants are grounded, so it is used to attract the charged dust particle.
C. Velocity of at between the plates must be low.
D. Electrodes wires that are maintained at hundred volts produces corona.

Answer

To solve the question regarding which statement is incorrect about electrostatic precipitators, we will analyze each option provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding Electrostatic Precipitators (ESPs)**:
- ESPs are devices used to remove particulate matter from exhaust gases in industrial applications, particularly in thermal power plants. They utilize electrostatic forces to attract and collect dust particles.

2. **Analyzing Option A**:
- **Statement**: "Electrostatic precipitator can remove over 99% of particulate matter present in exhaust from a thermal power plant."
- **Evaluation**: This statement is correct. ESPs are known for their high efficiency in removing particulate matter, often exceeding 99%.

3. **Analyzing Option B**:
- **Statement**: "Collecting plates are grounded, so it is used to attract the charged dust particle."
- **Evaluation**: This statement is also correct. The collecting plates in an ESP are grounded to attract the negatively charged dust particles, allowing them to settle on the plates.

4. **Analyzing Option C**:
- **Statement**: "Velocity between the plates must be low."
- **Evaluation**: This statement is correct as well. A low velocity of air between the plates is necessary for the dust particles to settle effectively on the collecting plates.

5. **Analyzing Option D**:
- **Statement**: "Electrode wires that are maintained at 100V produce corona."
- **Evaluation**: This statement is incorrect. In electrostatic precipitators, the electrodes are typically maintained at several thousand volts (not just 100 volts) to generate the necessary corona discharge for effective operation.

### Conclusion:
After evaluating all the options, the incorrect statement is **Option D**: "Electrode wires that are maintained at 100V produce corona."

### Final Answer:
**Option D is the incorrect statement about electrostatic precipitators.**

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