Question

A system in equilibrium is divided into two equal parts. The systems before and after the division, with respective state variables are as shown below.

Then, from the above, we can say that

• A. $U$ is an extensive state variable, whereas $M$ and $T$ are intensive state variables
• B. $T$ is an extensive state variable, whereas $U$ and $M$ are intensive state variables
• C. $U$ and $M$ are extensive state variables, whereas $T$ is intensive state variable
• D. $U,M$ and $T$ all are extensive state variables

Answer 1

Answer: (C)

Extensive state variables indicate the size of the system, whereas intensive do not.
So, if the system in equilibrium is divided into two equal parts, the variables that remain unchanged for each part are intensive.
On contrary, the variables whose values get halved in each part are extensive.
So, from the given values, we can say that $U$ (internal energy) and $M$ (mass) are extensive state variables and $T$ (temperature) is an intensive state variable.