Question

which energy transformation occurs in the core of a nuclear reactor? nuclear energy → mechanical energy nuclear energy → thermal energy thermal energy → nuclear energy mechanical energy → nuclear energy

Explanation:

In a nuclear reactor core, nuclear fission occurs. During fission, the mass - defect is converted into energy according to Einstein's $E = mc^{2}$. This energy is released in the form of heat (thermal energy). So the energy transformation is from nuclear energy to thermal energy.

Answer:

nuclear energy → thermal energy