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Why the slope of voltage-resistance characteristic increases in the case of tungsten lamp and decresing in case of carbon lamp?
Wiki User
∙ 10y ago
If the filament really was made from a material that has a negative temperature coefficient (as temperature increases, resistance decreases) then the decreasing resistance would cause more and more current to be taken as the lamp heated up and the temperature would get higher and higher in a runaway manner until either the power supply's breaker would trip or (more likely) the light bulb's filament would simply burn open.
In fact the filament has to be made from a material that has a positive temperature coefficient. (As temperature increases, resistance increases.) Then, as the bulb's temperature rises, its filament's increasing resistance causes less current to be taken than when it was cold. Quite quickly a stable "steady-state" temperature and "running" resistance is reached so that the bulb simply continues to give out a steady amount of light according to the current it is taking from the electricity supply.
Wiki User
∙ 10y ago
Wiki User
∙ 11y agofor Tungsten lamp the slope of the curve is positive where for carbon it is negative
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Tungsten's original name is Wolfram that is why the symbol for Tungsten is a W
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We should be strong as tungsten heavy alloy,tough as tungsten carbide.This is the motto of China Tungsten Online
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In the environment tungsten: * acidifies soils * impacts soil microbial commnities * decreases bacterial species in soil * increases fungal types in soil * kills red worms and plants * enters the food chain
What is the classification of tungsten?
Tungsten is classified as a metal.
