Lightning is a huge electric spark in the atmosphere between the clouds and the ground or the air. In the initial stages of formation, air behaves as an insulator between negative and positive charges in the cloud and between the ground and the cloud.
Lightning is a naturally occurring electrostatic discharge during which electrically activated regions, with one on the ground or both in the atmosphere, briefly neutralise themselves, generating the instantaneous discharge of an average of one energy gigajoule. This release may create a wide spectrum of electromagnetic radiation, from heat energy produced by the vigorous motion of electrons to bright flashes of visible light as black body radiation. Lightning creates thunder, a sound from the shock waves, which develops as gases in the discharge encounter a sudden expansion in pressure. Lightning usually happens during thunderstorms and other forms of high voltage weather phenomena. Volcanic lightning can also be generated during volcanic eruptions.
Cloud-to-cloud, cloud-to-air and cloud-to-ground are the three types of lightning. The three types of lightning are differentiated in terms of where they exist. It may occur between a ground and a ground, between two different clouds or inside a single thundercloud. Numerous other observational variants are identified, including heat-lightning. It can be visible from a large distance, but it will not be audible. Dry lightning causes forest fires. There is another type called ball lightning, which is sparingly detected scientifically.
Electrostatic discharge usually occurs when two particular conditions are satisfied. Primarily, a sufficiently large potential difference between the two space regions should exist. Secondly, a medium with high resistance must block the unimpeded, free equalisation of the opposite charges. The atmosphere acts as an electrical barrier or insulation that stops free electrical equalisation between charged areas of opposite polarity. In most cases, there is a charge accumulation and separation in particular areas of the cloud during a thunderstorm. The exact processes through which this happens are still unknown.
When a thundercloud travels over the Earth’s surface, an equal charge with opposite polarity is induced on the surface under the cloud. The generated positive surface charge will be less at a fixed point as the thundercloud approaches. It will increase as the storm’s centre reaches and drops as the thunderclouds travel. The approximate value of the induced surface charge can be roughly denoted as a bell curve. The oppositely charged areas produce an electric field within the air existing between them. This electric field changes in accordance with the strength of the surface charge on the thundercloud’s base. The electric field will increase as the accumulated charge increases.
The video explains the reason behind the glowing of lightning bolts.
Important Lightning Questions with Answers
1) What is lightning?
Lightning is a huge electric spark in the atmosphere between the clouds, the ground or the air. In the initial stages of formation, air behaves as an insulator between negative and positive charges in the cloud and between the ground and the cloud.
2) Explain the characteristics of lightning.
Lightning is a naturally occurring electrostatic discharge during which electrically activated regions, with one on the ground or both in the atmosphere, briefly neutralise themselves, generating the instantaneous discharge of an average of one energy gigajoule. This release may create a wide spectrum of electromagnetic radiation, from heat energy produced by the vigorous motion of electrons to bright flashes of visible light as black body radiation. Lightning creates thunder, a sound from the shock waves, which develops as gases in the discharge encounter a sudden expansion in pressure. Lightning usually happens during thunderstorms and other forms of high voltage weather phenomena. Volcanic lightning can also be generated during volcanic eruptions.
3) What are the main types of lightning?
Cloud-to-cloud, cloud-to-air and cloud-to-ground are the three types of lightning. The three types of lightning are differentiated in terms of where they exist. It may occur between a ground and a ground, between two different clouds or inside a single thundercloud. Numerous other observational variants are identified, including heat-lightning. It can be visible from a large distance, but it will not be audible. Dry lightning causes forest fires. There is another type called ball lightning, which is sparingly detected scientifically.
4) How do electric discharges occur?
Electrostatic discharge usually occurs when two particular conditions are satisfied. Primarily, a sufficiently large potential difference between the two space regions should exist. Secondly, a medium with high resistance must block the unimpeded, free equalisation of the opposite charges. The atmosphere acts as an electrical barrier or insulation that stops free electrical equalisation between charged areas of opposite polarity. In most cases, there is a charge accumulation and separation in particular areas of the cloud during a thunderstorm. The exact processes through which this happens are still unknown.
5) Explain what happens when a thundercloud passes near the Earth’s surface.
When a thundercloud travels over the Earth’s surface, an equal charge with opposite polarity is induced on the surface under the cloud. The generated positive surface charge will be less at a fixed point as the thundercloud approaches. It will increase as the storm’s centre reaches and drops as the thunderclouds travel. The approximate value of the induced surface charge can be roughly denoted as a bell curve. The oppositely charged areas produce an electric field within the air existing between them. This electric field changes in accordance with the strength of the surface charge on the thundercloud’s base. The electric field will increase as the accumulated charge increases.
6) _____ is a huge electric spark in the atmosphere between the clouds, the ground or the air.
Answer: Lightning
Explanation: Lightning is a huge electric spark in the atmosphere between the clouds, the ground or the air.
7) _____lightning can be generated during volcanic eruptions.
Answer: Volcanic
Explanation: Volcanic lightning can be generated during volcanic eruptions.
8) The _____ acts as an electrical barrier or insulation that stops free electrical equalisation between charged areas of opposite polarity.
Answer: atmosphere
Explanation: The atmosphere acts as an electrical barrier or insulation that stops free electrical equalisation between charged areas of opposite polarity.
9) _____ lightning is an electric discharge between the ground and a thundercloud.
Answer: Cloud-to-ground
Explanation: Cloud-to-ground lightning is an electric discharge between the ground and a thundercloud. `
10) When lightning occurs between two clouds, it is called _____ lightning.
Answer: cloud-to-cloud
Explanation: When lightning occurs between two clouds, it is called cloud-to-cloud lightning.
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Practice Questions
1) What is meant by electrostatic induction?
2) What are the main types of clouds that cause lightning?
3) What is ball lightning?
4) What is heat lightning?
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