Any change of the energy of a system occurs because of
A) energy transfer across the boundaries of the system.
B) combustion of fuels within the system.
C) radioactive decay of elements within the system.
D) all of the above.
E) only (b) and (c) above.

Question

Quizplus · Accepted Answer

The first law of thermodynamics states that the energy of a system is conserved, meaning that any change in energy must come from transfer of energy across the boundaries of the system, whether it be in the form of heat or work. Combustion of fuels and radioactive decay may occur within the system, but they still involve energy transfer across the boundaries of the system. Therefore, the correct choice is A.

Any Change of the Energy of a System Occurs Because