Question

in the first law of thermodynamics, $delta e = q - w$, what does $delta e$ stand for?
the heat added to the system
the internal energy of the system
the change in the internal energy of the system
the work done by the piston

Explanation:

In the first law of thermodynamics, the symbol $\Delta$ denotes a change in a quantity. The formula $\Delta E = Q - W$ describes the relationship between energy transfer and internal energy change for a system. $Q$ is heat added to the system, $W$ is work done by the system, and $\Delta E$ represents the resulting change in the system's internal energy.

Answer:

the change in the internal energy of the system