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| Lightning and Lightning Conductors |
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| During thunderstorms, large amount of electrical charge separation takes place in the clouds. As a result, some regions of the cloud have overall positive charge, while others have overall negative charge. When this separation becomes sufficient, the air ionizes and becomes conducting. This results in a flash of lightning. Most lightnings occur between the two parts of the same cloud, but it can take place between two clouds or between a cloud and earth also. In that case the lightning flows throughout the air to the earth and strikes the sharpest object on the earth. Sometimes these flashes can be as long as 150 km. |
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| Lightning conductors are normally fitted on the top of tall buildings as a safety device to protect them from the destructive effects caused by lightning. It consists of a few metal spikes fitted to the highest part of the building and connected to a thick copper strip which is buried deep in the earth. During a storm, a thundercloud with a negative charge may build up above the conductor as shown in figure. |
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| A positive charge is then induced at the pointed ends of the conductor. As the conductor has sharp pointed ends, the induced positive charge gets discharged in the atmosphere. This neutralizes the negatively charged cloud and thus stops the lightning from taking place. |
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