What condition is necessary for the flow of heat? What analogous condition is necessary for the flow of charge

Answer 1

1. A temperature differential and a conductive medium is necessary for heat to flow. (note: heat may also flow by means of radiation which does not require a conductive medium).
or
2. A heat engine (i.e. refrigerator) is necessary to add energy to a heat source to move it to a heat 'sink' where the temperature is higher.

The analogy for charge is; a potential difference (voltage) and an (electrically) conductive medium is necessary for charge to flow.

A loose analogy to number 2., above, would be something like a Van deGraff generator.

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