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Dear Editor,
Admittedly a minor pedantic point on an article published 13 years ago, but I thought it worth pointing out a possible (albeit inconsequential) mistake in the formula provided for the amount of heat generated by an electrical current passing through the body, given in the article as 0.24 x (voltage^2) x resistance. This presumably refers to Joule’s law which gives the power dissipated by an electrical conductor. Power through a conductor is given by voltage x current (P=VI) which by Ohm’s law (V=IR) gives P=(I^2)R=(V^2)/R (the factor of 0.24 is a conversion from Joules to calories). Thus the correct expression for the heat in calories dissipated by a current (per second) should be either 0.24 x (current^2) x resistance or 0.24 x (voltage^2)/resistance. A check of units makes the expression in the paper appear incorrect since resistance has units J/(s x A^2).
Kind regards,
Agesilaus Churchill
Re: Pathophysiology and types of burns
Dear Editor,
Admittedly a minor pedantic point on an article published 13 years ago, but I thought it worth pointing out a possible (albeit inconsequential) mistake in the formula provided for the amount of heat generated by an electrical current passing through the body, given in the article as 0.24 x (voltage^2) x resistance. This presumably refers to Joule’s law which gives the power dissipated by an electrical conductor. Power through a conductor is given by voltage x current (P=VI) which by Ohm’s law (V=IR) gives P=(I^2)R=(V^2)/R (the factor of 0.24 is a conversion from Joules to calories). Thus the correct expression for the heat in calories dissipated by a current (per second) should be either 0.24 x (current^2) x resistance or 0.24 x (voltage^2)/resistance. A check of units makes the expression in the paper appear incorrect since resistance has units J/(s x A^2).
Kind regards,
Agesilaus Churchill
Competing interests: No competing interests