Light bulbs use very fine filaments to increase the resistance.With the increase in resistance the filament gets heated and starts glowing. By reducing the cross section of the filament the intention is always to increase the amount of resistance, so that when current passes the filament glows with heat. The filament of the bulbs are mostly made of tungsten because it has the capacity to withstand huge amount of heat. If other metals are used in place of tungsten, then it will not be able to withstand the high temperature generated and the filament will get broken very quickly.
