Which radioactive isotope is most commonly utilized as the heat source in Radioisotope Thermoelectric Generators (RTGs)?

Answer

Plutonium-238 ($^{238} ext{Pu}$)

Radioisotope Thermoelectric Generators rely on the continuous decay heat produced by a specific radioactive isotope, which is most often Plutonium-238, to generate steady electrical power.

Which radioactive isotope is most commonly utilized as the heat source in Radioisotope Thermoelectric Generators (RTGs)?
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