Problem solving - BMAT 2016

A defibrillator provides an electric shock to a heart to restore its normal rhythm. The energy to do this is 125 J, at a steady voltage of 500 V, for a time of 10 milliseconds. What is the current during this process?

I used V= I * R, i got 5, and the answer is 25.

hi

you can’t use V=IR since we don’t have a value for the resistance
instead we use Power=IV and Power=Energy/time

10 milliseconds = 10 * 10⁻³ seconds = 10⁻² seconds
P = E/t = 125/10⁻² = 12500 watts

P=IV so I=P/V
I = 12500/500 = 25 Amperes

hope this helps!

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