Закон Ома для полной цепи имеет вид:
I(R+r) = \epsilon => IR + Ir = \epsilon => U + Ir = \epsilon => Ir = \epsilon - U => r = \frac{\epsilon - U}{I}\\ I_{kz} = \frac{\epsilon}{r} = \frac{\epsilon}{\frac{\epsilon - U}{I}} = \frac{\epsilon I}{\epsilon - U} = \frac{4*2}{4 - 3.6} = \frac{8}{0.4} = 20 A" alt="I = \frac{\epsilon}{R+r} => I(R+r) = \epsilon => IR + Ir = \epsilon => U + Ir = \epsilon => Ir = \epsilon - U => r = \frac{\epsilon - U}{I}\\ I_{kz} = \frac{\epsilon}{r} = \frac{\epsilon}{\frac{\epsilon - U}{I}} = \frac{\epsilon I}{\epsilon - U} = \frac{4*2}{4 - 3.6} = \frac{8}{0.4} = 20 A" align="absmiddle" class="latex-formula">