Y’know, that bit of techno-gibberish always bothered me. After all, a weak light bulb is 40 Watts. Maybe if he says “40 Megajoule” it would be okay. But he didn’t.
Kind of like Han Solo talking about the Falcon making the Kessel Run in less than twelve parsecs.
40 Watts for a light bulb means it consumes 40 Watts of electricity. A 40 Watt laser means 40 Watts of output coherent light. See here for a video of a 40W laser used for cutting and engraving: http://m.youtube.com/watch?v=MBj1uc8_vF0&desktop_uri=%2Fwatch%3Fv%3DMBj1uc8_vF0 Still not weapon level, but does more than a 40W light bulb. (OK, maybe it should have been 400W - that would be a decent weapon.)