Answer:
If the work is done by the system then the internal energy of the system will decrease.
Explanation:
Given that work is being done in an adiabatic system, does the internal energy in the system increase or decrease?
An adiabatic process is a thermodynamic process in which there is no heat flow going in or out of a system.
We can use the first law of thermodynamics to answer the question. The first law of thermodynamic is a restatement of energy conservation. Energy is not created or destroyed it is simply transformed into other forms of energy. We can summarize this law in the following equation(s).
[tex]\boxed{\left\begin{array}{ccc}\text{\underline{The First Law of Thermodynamics:}}\\\\\Delta E_{int.}=Q+W_{on}\\ \text{or}\\\Delta E_{int.}=Q-W_{by}\end{array}\right}[/tex]
Since no heat is being exchanged between the system and its surroundings. We can say that Q=0 J. Substituting this in we have...
[tex]\Delta E_{int.}=Q+W_{on} \ \text{or} \ \Delta E_{int.}=Q-W_{by}\\\\\Longrightarrow \Delta E_{int.}=0+W_{on} \ \text{or} \ \Delta E_{int.}=0-W_{by} \\\\\therefore \boxed{\Delta E_{int.}=W_{on} \ \text{or} \ \Delta E_{int.}=-W_{by}}[/tex]
Thus, in an adiabatic process the change in internal energy is solely determined by the work done on or by the system. So we can conclude that the internal energy increases if the work is done on the system or that the internal energy decreases if the work is done by the system.
In the case of this question it is asking about work done by the system.
∴ If the work is done by the system then the internal energy of the system will decrease.
