Which of the statements A–D is false?

Question

A. The purpose of a turbine in a steam power plant is to convert the internal energy of the steam into electrical energy.
B. The mass flow rate in a pipe is equal to the product of the fluid density, cross-sectional area of the pipe and the fluid velocity.
C. For a steady-state system with only one stream entering and one stream leaving the system, the volumetric flow rate of the entering stream must be equal to the volumetric flow rate of the exiting stream.
D. In a Rankine cycle, the condenser operates at a lower temperature than the boiler.
E. None of the above is false.

Answer 1

A. Incorrect. This statement is true. Conceptually, the shaft work in a Rankine engine can be used for anything. In a steam power plant it is used to make electricity.
B. Incorrect. This statement is true. Example 1-5 shows the use of this equation.
C. Correct. Volume is not a conserved quantity. The mass flow rates of the entering and leaving stream are equal at steady state, but if they have different densities, they will have different volumetric flow rates.
D. Incorrect. This statement is true. There is a large pressure drop in the turbine. Because the pressure of the fluid entering the condenser is lower than the pressure of the fluid leaving the boiler, the boiling point of the fluid is lower, so the condenser operates at a lower temperature.
E. Incorrect. Check again. One of the statements is false.