Test: Thermodynamic Properties & Compressibility - Mechanical Engineering MCQ

Explanation: For process to be adiabatic, there is no heat exchange and no heat generation within fluid.

Explanation: As, specific volume remains constant, density remains constant. Therefore for given temperature there is no change in volume. hence, the process is isothermal.

Explanation: If fluid is incompressible there is not much change in observed properties with variation in temperature and pressure. Hence, no perceivable change.

Explanation: For isothermal process
K=p
For adiabatic process
K=kp
where K=Bulk modulus
k=Polytropic constant
p=Pressure.

Explanation: The value of gas constant depends on molecular weight. As the molecular weight is different, gas constant will be different.

Explanation: Ideal gas Law: PV=nRT
n=M/m
P=(9*8314*293)/28.97=946 kN/m².

Explanation: R=P/(ρ*T)=3500000*9.81/16*303=708.23.

Explanation: For polytropic process,

P2=(v1/v2)n *P1
=(0.8/0.3)1.3 * 0.4 ……..(for superheated stream n=1.3)
=.74 N/m2
T1=P1v1/nR=422.3℃.

Explanation: Compressibility=1/Bulk Modulus
=1/K
K=(dp*V/dv)
=60/0.15
=400
Compressibility=.0025.

Explanation: cp is molar heat capacity at constant pressure. As temperature is increased, enthalpy increases, heat capacity increases.
Same is for cv, cp is molar heat capacity at constant volume.
However cp-cv=R and cp/cv = R
Hence, as cp, cv increases R decreases.