Problem $3$: True or False $(30$ points total, $5$ points per correct answer$)$

In a closed system, while the entropy production can only be greater or equal than zero, the entropy transfer can be grater than zero, equal to zero or less than zero.

The isentropic turbine efficiency ${}_T$ of a real turbine is equal to $1.$

The specific entropy $s^0(T)$ of an ideal gas is zero when the absolute temperature is $0$ K and the absolute pressure is $0$ Pa $.$

For any real process of an isolated system, the total entropy is always conserved.

It is impossible for a commercial refrigerator to follow an inverse Carnot cycle.

The thermal efficiency of a thermal engine is equal to $100\%$ only in the theoretical case of a reversible process, but, in reality, it is always less than $100\%.$