250+ TOP MCQs on Velocity of Pressure Pulse in a Fluid and Stagnation Properties and Answers

Thermodynamics Multiple Choice Questions on “Velocity of Pressure Pulse in a Fluid and Stagnation Properties”.

1. An incompressible fluid is one for which density does not change with change in ____
a) pressure
b) temperature
c) velocity
d) all of the mentioned
Answer: d
Clarification: In an incompressible fluid, either density does not change or changes very little.

2. A compressible fluid is one for which density changes with change in temperature, pressure or velocity.
a) true
b) false
Answer: a
Clarification: This is opposite to an incompressible fluid.

3. Liquids are ____ and gases are ____
a) both are compressible
b) both are incompressible
c) incompressible, compressible
d) compressible, incompressible
Answer: c
Clarification: Liquids are incompressible whereas gases are compressible.

4. The pressure wave velocity c is given by
a) 1 / (dp/d(density))
b) sqrt(dp/d(density))
c) sqrt(d(density)/dp)
d) (dp/d(density))
Answer: b
Clarification: Here dp is the change in pressure.

5. For an ideal gas, velocity of sound is given by
a) 1/ɣ*R*T
b) sqrt(1/ɣ*R*T)
c) sqrt(ɣ/RT)
d) sqrt(ɣ*R*T)
Answer: d
Clarification: Here R is the characteristic gas constant.

6. The lower the molecular weight of fluid, ____ the value of ɣ and ____ is the sonic velocity at same temperature.
a) lower, lower
b) higher, higher
c) lower, higher
d) higher. lower
Answer: b
Clarification: This comes from the expression of velocity of sound in an ideal gas.

7. The Mach number is given by
a) (c/V)²
b) (V/c)²
c) V/c
d) c/V
Answer: c
Clarification: Here V is the actual velocity and c is the sonic velocity.

8. For the isentropic stagnation state,
a) it is a reference state
b) designated with subscript zero
c) both of the mentioned
d) none of the mentioned
Answer: c
Clarification: It is a reference state in compressible fluid flow.

9. The reference temperature To and normal temperature T are related by
a) (To/T) = 1 + (V²)/(2*cp*T)
b) (To/T) = 1 – (V²)/(2*cp*T)
c) (To/T) = 1 + (V²)/(cp*T)
d) (To/T) = 1 – (V²)/(cp*T)
Answer: a
Clarification: Here cp is the specific heat at constant pressure and V is the actual velocity.

10. The reference temperature To and normal temperature T can be related in terms of M by
a) (To/T) = 1 + (ɣ-1)*(M²)
b) (To/T) = 1 + (ɣ-1)*(M²)/2
c) (To/T) = 1 – (ɣ-1)*(M²)/2
d) (To/T) = 1 – (ɣ-1)*(M²)
Answer: b
Clarification: Here M is the Mach number.