(Multiple choice)

(1)

On a humid day, water vapor condenses on a cold surface. During condensation, the entropy of the water 

(a) Increases. 

(b) Remains constant. 

(c) Decreases. 

(d) May decrease or remain unchanged.

(2)

In a reversible adiabatic process, 

(a) The internal energy of the system remains constant. 

(b) No work is done by the system. 

(c) The entropy of the system remains constant. 

(d) The temperature of the sy stem remains constant.

(3) True or false: 

(a) Work can never be converted completely into heat. 

(b) Heat can never be converted completely into work. 

(c) All heat engines have the same efficiency. 

(d) It is impossible to transfer a given quantity of heat from a cold reservoir to a hot reservoir. 

(e) The coefficient of performance of a refrigerator cannot be greater than 1. 

(f) All Carnot engines are reversible. 

(g) The entropy of a system can never decrease. 

(h) The entropy of the universe can never decrease.

(4)

An ideal gas is taken reversibly from an initial state P_i, V_i, T_i to the final state P_f, V_f, T_f. Two possible paths are (A) an isothermal expansion followed by an adiabatic compression, and (B) an adiabatic compression followed by an isothermal expansion. For these two paths, 

(a) ∆U_A > ∆U_B. 

(b) ∆S_A > ∆S_B. 

(c) ∆S_A < ∆S_B. 

(d) None of the above is correct.