= Solution
For the <entropy balance of a thermostatted resistor>, electrical work becomes <heat> $Q=I^2Rt=2.0\times10^7\,\mathrm J$. At fixed <temperature> the <resistor> has no net change of <thermodynamic state>; it exports this <heat> to its thermostat. Treating the electrical supply as a source of work,
$$
\boxed{\Delta S_{\rm resistor}=0,\qquad \Delta S_{\rm universe}=\frac{I^2Rt}{T}=6.67\times10^4\,\mathrm{J\,K^{-1}}.}
$$
<Entropy> is produced by <Joule heating> even though it does not accumulate in the <resistor>. Additional <entropy production> inside a nonideal <power> supply is outside the specified model.
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