Define Corona, List its causes and state how can it be avoided. (two each)
2 Answers
**Corona** (or COVID-19) is an infectious disease caused by the SARS-CoV-2 virus. It primarily spreads through respiratory droplets and affects the respiratory system, potentially leading to severe illness or complications.
### Causes:
1. **Human-to-Human Transmission:** The virus spreads mainly through close contact with an infected person, particularly through respiratory droplets released when they cough, sneeze, or talk.
2. **Contaminated Surfaces:** The virus can survive on surfaces for varying periods, and touching contaminated surfaces followed by touching the face can lead to infection.
### Prevention:
1. **Vaccination:** Getting vaccinated reduces the risk of severe illness and transmission of the virus.
2. **Hygiene Practices:** Regular handwashing with soap and water, or using hand sanitizer, along with wearing masks in crowded places, helps limit the spread.
By following these measures, the risk of contracting or spreading COVID-19 can be significantly reduced.
### Causes:
1. **Human-to-Human Transmission:** The virus spreads mainly through close contact with an infected person, particularly through respiratory droplets released when they cough, sneeze, or talk.
2. **Contaminated Surfaces:** The virus can survive on surfaces for varying periods, and touching contaminated surfaces followed by touching the face can lead to infection.
### Prevention:
1. **Vaccination:** Getting vaccinated reduces the risk of severe illness and transmission of the virus.
2. **Hygiene Practices:** Regular handwashing with soap and water, or using hand sanitizer, along with wearing masks in crowded places, helps limit the spread.
By following these measures, the risk of contracting or spreading COVID-19 can be significantly reduced.
**Corona Discharge**
**Definition:**
Corona discharge is a phenomenon where a current flows through a gas (usually air) around a conductor that is at a high voltage. This results in the ionization of the surrounding air, creating a visible glow, and sometimes audible noise, often seen as a bluish or purplish light. It occurs when the electric field around the conductor becomes strong enough to ionize the surrounding air.
**Causes of Corona Discharge:**
1. **High Electric Field:**
- When the electric field strength around a conductor exceeds a certain threshold, it can ionize the surrounding air. This usually happens when there is a sharp edge or point on the conductor, which creates a high localized electric field. For example, overhead power lines with sharp edges or damaged insulation can create a high electric field leading to corona discharge.
2. **Poor Insulation or Insulator Contamination:**
- If the insulation around a conductor is degraded or contaminated with dirt, moisture, or other substances, it can lower the breakdown voltage of the insulation. This makes it easier for the electric field to exceed the breakdown voltage of the air, leading to corona discharge.
**How to Avoid Corona Discharge:**
1. **Smooth Conductor Design:**
- Using conductors with smooth, rounded surfaces can help reduce the electric field intensity around sharp edges or points. High-voltage power lines are often designed with larger diameter conductors or bundled conductors to ensure a more uniform electric field and minimize the chances of corona discharge. Additionally, incorporating shielding and grading can help control and distribute the electric field more evenly.
2. **Improved Insulation:**
- Ensuring that conductors and electrical equipment are well insulated and free from contaminants is crucial. Regular maintenance and inspection of insulation materials can prevent degradation and contamination. In cases where high voltages are involved, using high-quality, specialized insulation materials that can withstand the electric field strengths involved can also help reduce the risk of corona discharge.
By addressing these causes and implementing preventive measures, the incidence of corona discharge can be minimized, leading to more reliable and efficient electrical systems.
**Definition:**
Corona discharge is a phenomenon where a current flows through a gas (usually air) around a conductor that is at a high voltage. This results in the ionization of the surrounding air, creating a visible glow, and sometimes audible noise, often seen as a bluish or purplish light. It occurs when the electric field around the conductor becomes strong enough to ionize the surrounding air.
**Causes of Corona Discharge:**
1. **High Electric Field:**
- When the electric field strength around a conductor exceeds a certain threshold, it can ionize the surrounding air. This usually happens when there is a sharp edge or point on the conductor, which creates a high localized electric field. For example, overhead power lines with sharp edges or damaged insulation can create a high electric field leading to corona discharge.
2. **Poor Insulation or Insulator Contamination:**
- If the insulation around a conductor is degraded or contaminated with dirt, moisture, or other substances, it can lower the breakdown voltage of the insulation. This makes it easier for the electric field to exceed the breakdown voltage of the air, leading to corona discharge.
**How to Avoid Corona Discharge:**
1. **Smooth Conductor Design:**
- Using conductors with smooth, rounded surfaces can help reduce the electric field intensity around sharp edges or points. High-voltage power lines are often designed with larger diameter conductors or bundled conductors to ensure a more uniform electric field and minimize the chances of corona discharge. Additionally, incorporating shielding and grading can help control and distribute the electric field more evenly.
2. **Improved Insulation:**
- Ensuring that conductors and electrical equipment are well insulated and free from contaminants is crucial. Regular maintenance and inspection of insulation materials can prevent degradation and contamination. In cases where high voltages are involved, using high-quality, specialized insulation materials that can withstand the electric field strengths involved can also help reduce the risk of corona discharge.
By addressing these causes and implementing preventive measures, the incidence of corona discharge can be minimized, leading to more reliable and efficient electrical systems.