With the long incandescent bulb wall black, it is experienced which changes are formed below
Tell the incandescent filament after the temperature rise, tungsten wire part of the sublimation into gas
Judgment of changes in the state of the method is: first determine the state before the change, and then determine the state after the change
Examine the ability to determine the state changes
Gaseous tungsten encountered cold inside the lamp condensate into a solid tungsten, attached to the incandescent bulb wall, so that the inner wall of the lamp black.
