Combustion gases with a specific heat ratio of 1.34 enter an adiabatic nozzle steadily at 720°C and 400 kPa with a low velocity, and exit at a pressure of 100 kPa. The lowest possible temperature of combustion gases at the nozzle exit is
A)426°C
B)507°C
C)699°C
D)112°C
E)363°C

Question

Quizplus · Accepted Answer

Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 
k=1.34
T1=720 "C"
P1=400 "kPa"
P2=100 "kPa"
"Nozzle exit temperature will be lowest for isentropic operation"
T2=(T1+273)*(P2/P1)^((k-1)/k)-273
"Some Wrong Solutions with Common Mistakes:"
W1_T2=T1*(P2/P1)^((k-1)/k) "Using C for temperature"
W2_T2=(T1+273)*(P2/P1)^((k-1)/k) "Not converting the answer to C"
W3_T2=T1*(P2/P1)^k "Using wrong relation"

Combustion Gases with a Specific Heat Ratio of 1