Convection: Heat transfer using mass motion though liquids
Radiation: Heat transfer using electromagnetic waves.
Heat that comes from a heat lamp in a bathroom mostly relates to radiation. Not only because heat lamps give off light but also because radiation is used to heat its surroundings which the heat lamp in your example is doing.
The answer would be radiation. Heat lamps give off IR radiation in order to heat the surroundings. No idea what you mean by "potential" in reference to heat transfer.