Answer: What do you mean by a metzius of “light”? Vos shtait da? Does the thing give off a chalos light or not?! Fakert, if – and to the extent, the cheftza needs switching, it is no longer in the geder mesuyam of “light bulb”, so your Kashe is pashut narishkeit! Da’as ba’alei batim hepech da’as Brisker Torah”. Don’t make faces; only eineklach may do so. You chap? Ya? Nu nu.
Also, Der Tatteh never said nothing about this ‘switching lightbulbs’ zach. Except… someone once takeh told me he thinks, maybe in this inyan of an old bulb – or maybe about an old broom, Der Tatteh said in Yiddishe shprach – and this absolutely cannot be translated into Lashon Hakodesh, and I forbid it with a shiyur bakinyan, Medin Yerusha: “מ’קען זיין בעסער”. It was exactly those words with precisely such a facial expression.