Fluid Mechanics and Thermal Sciences - Online Test
Q1. The stroke and bore of a four stroke spark ignition engine are 250 mm and
200 mmrespectively. The clearance volume is 0.001 m3. If the specific heat ratio γ = 1.4, the air-standard cycle efficiency of the engine is
Answer : Option C
Explaination / Solution:
No Explaination.
Q2. A building has to be maintained at 21oC (dry bulb) and 14.5oC (wet bulb).
The dew point temperature under these conditions is 10.17oC. The outside
temperature is
-23oC (dry bulb) and the internal and external surface heat
transfer coefficients are 8 W/m2K and 23 W/m2K respectively. If the building
wall has a thermal conductivity of 1.2 W/m K, the minimum thickness (in m) of
the wall required to prevent condensation is
Answer : Option B
Explaination / Solution:
No Explaination.
Q3. Atmospheric air at a flow rate of 3 kg/s (on dry basis) enters a cooling and dehumidifying coil with an enthalpy of 85 kJ/ kg of dry air and a humidity ratio of 19 grams/kg of dry air. The air leaves the coil with an enthalpy of 43 kJ/kg of dry air and a humidity ratio of 8 grams/kg of dry air. If the condensate water leaves the coil with an enthalpy of 67 kJ/kg, the required cooling capacity of the coil in kW is
Answer : Option C
Explaination / Solution:
No Explaination.
Q4. A heat transformer is device that transfers a part of the heat, supplied to it at an intermediate temperature, to a high temperature reservoir while rejecting the remaining part to a low temperature heat sink. In such a heat transformer, 100 kJ of heat is supplied at 350 K. The maximum amount of heat in kJ that can be transferred to 400 K, when the rest is rejected to a heat sink at 300 K is
Answer : Option D
Explaination / Solution:
No Explaination.
Q5. Which combination of the following statements is correct ?
The incorporation of reheater in a steam power plant :
P : always increases the thermal efficiency of the plant.
Q : always increases the dryness fraction of steam at condenser inlet
R : always increases the mean temperature of heat addition.
S : always increases the specific work output.
Answer : Option B
Explaination / Solution:
No Explaination.
Q6. Which combination of the following statements is correct ?
P : A gas cools upon expansion only when its Joule-Thomson coefficient is
positive in the temperature range of expansion.
Q : For a system undergoing a process, its entropy remains constant only when
the process is reversible.
R : The work done by closed system in an adiabatic is a point function.
S : A liquid expands upon freezing when the slope of its fusion curve on
pressure-Temperature diagram is negative
Answer : Option A
Explaination / Solution:
No Explaination.
Q7. Which combination of the following statements about steady incompressible
forced vortex flow is correct ?
P: Shear stress is zero at all points in the flow.
Q: Vorticity is zero at all points in the flow.
R: Velocity is directly proportional to the radius from the center of the vortex.
S: Total mechanical energy per unit mass is constant in the entire flow field.
Answer : Option B
Explaination / Solution:
No Explaination.
Q8. Match List-I with List-II and select the correct answer using the codes given
below the lists :
Codes:
Answer : Option A
Explaination / Solution:
No Explaination.
Q9. A block of mass
M is released from point P on a rough inclined plane with
inclination angle θ, shown in the figure below. The co-efficient of friction is μ.
If μ < tanθ, then the time taken by the block to reach another point Q on the
inclined plane, where PQ = s, is
Answer : Option A
Explaination / Solution:
No Explaination.
Q10. A 200 × 100 × 50 mm steel block is subjected to a hydrostatic pressure of 15
MPa.
The Young’s modulus and Poisson’s ratio of the material are 200 GPa and 0.3
respectively. The change in the volume of the block in mm2 is
Answer : Option B
Explaination / Solution:
No Explaination.
