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Question
State two advantages of filling an inert gas in an evacuated electric filament lamp.
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Solution
(i) The inert gas is filled at very low pressure to prevent oxidation as well as evaporation and thus increases its life.
(ii) While bulb is working, a convection current is set-up within it which carries the spurting particles of tungsten upward towards the cap and hence the blackening of the lower part (transparent portion) of the bulb is avoided.
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