I'm trying to write a fantasy scifi story around magic being just another develop of energy. It would certainly be prefer power but via a few quirks. I am going to base the "power limit" (basically how a lot magic a perboy would certainly have the ability to safely manipulate) on exactly how a lot power is compelled to kill a human through 1.) Electricty 2.) Heat 3.) Ionizing(?) Radiation 4.) Level old blunt force

Electricity:

Generally a current with the heart in between 100 and 200 mA is thought about directly lethal with extremely little bit possibility of survival. Note that higher existing actually raises the opportunity of survival as the muscular cramps inhibits the heart from going right into ventricular fibrillation.

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Now, skin has actually a complicated voltage-current-resistance partnership, but if we think about a macroshock of around 220 V
50 Hz used on relatively big areas (i.e. ex. palms, or palm and sole) of wet skin on two significant limbs, where tright here is no compelled penetration of skin, an impedance of about 1400 Ohms is reasonable.

That gives us ~150 mA, right in the deadly selection. That offers ~34.5 W, so ~34.5 J/s. One second of expocertain is most probably lethal. If applied directly to the heart, a lot much less is needed to kill.

This formulation doesn't feel rather right for r/AskScienceDiscussion however the question is fun and I have actually time am procrastinating. If highly trained wizards have actually incredibly exact manage over the application of magic then killing a person doesn't take much:

Disclaimer: math has been half-assed

If you boiled the medulla oblongata, my guess is around 50 grams of tworry, heated to 100 oC from 37 oC, or 50x63x4.184 = 13,179 Joules.

This is the technique I prefer, yet if OP really wants to cheap out on power use they might obtain amethod via heating 1 g of medulla from 37 to 60°C, around 84 J (estimating brain specific warmth capacity 3.65 J/gC).