# Thermal Engineering 31

Objective Questions and Answer: Thermal Engineering 31

Subject: Thermal Engineering 31

Part 31: Objective questions and answers of Thermal Engineering

Q1. If partial pressure of air and steam Pa respectively in a condenser, then according to Dalton's law, the pressure in condenser is equal to

a) Ps-Pa

b) Pa-Ps

c) Pa+Pa

d) None Of These

Q2. Equivalent evaporation is the amount of water evaporated in a boiler from and at

a) 0°C

b) 100°C

c) Saturation temperature at given pressure

d) Room temperature

Q3. The specific volume of steam with increase in pressure decreases

a) Linearly

b) Slowly first and then rapidly

c) Rapidly first and then slowly

d) Inversely

Q4. The equivalent evaporation of a boiler is a measure to compare

a) The given boiler with the model

b) The two different boilers of the same make

c) Two different makes of boilers operating under the same operating conditions

d) Any type of boilers operating under any conditions.

Q5. The coal requirement per kw hour generation in the thermal power plant is of the order of

a) 0.1 to 0.2 kg

b) 0.2 to 0.4 kg

c) 0.6 to 0.8 kg

d) 1.0 to 1.5 kg

Q6. Sublimation region is the region where

a) Solid and vapour phases are in equilibrium

b) Solid and liquid phases are in equilibrium

c) Liquid and vapour phases are in equilibrium

d) Solid, liquid and vapour phases are in equilibrium

Q7. Stoichiometric quantity of air is the

a) Air present in atmosphere at NTP conditions

b) Air required for complete combustion of fuel with no excess air

c) Air required for optimum combustion so as to have reasonable excess air

d) Air required to convert CO into C02

Q8. One kg of steam sample contains 0.8 kg dry steam; its dryness fraction is

a) 0.2

b) 0.8

c) 1

d) 0.6

Q9. If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by

a) Throttling calorimeter

b) Separating calorimeter

c) Combined separating and throttling calorimeter

d) Bucket calorimeter

Q10. If xx and x2 be the dryness fractions obtained in separating calorimeter and throttling calorimeter respectively, then the actual dryness fraction of steam will be

a) Xx * x^2

a) xx + x^2

b) Xx-x^2

c) None of these

Q11. The specific heat of superheated steam in kcal/kg is generally of the order of

a) 0.1

b) 0.3

c) 0.5

d) 0.8

Q12. On Mollier chart, flow through turbine is represented by

a) Horizontal straight line

b) Vertical straight line

c) Straight inclined line

d) Curved line

Q13. A wet vapor can be completely specified by

a) Pressure only

b) Temperature only

c) Dryness fraction only

d) Pressure and dryness fraction.

Q14. On Millier chart, the constant pressure lines

a) Diverge from left to right

b) Diverge from right to left

c) Are equally spaced throughout

d) First rise up and then fall

Q15. On Mollier chart, free expansion, or throttling process from high pressure to atmosphere is represented by

a) Horizontal straight line

b) Vertical straight line

c) Straight inclined line

d) Curved line

Q16. The bituminous coal is non-caking if its carbon content is

a) 78-81%

b) 81-85%

c) 85-90%

d) 90-95%

Q17. The dry saturated steam at very low pressure, (5-10 kg/cm2) when throttled to atmosphere will become

a) Wet

b) Superheated

c) Remain dry saturated

d) Dry

Q18. Water at pressure of 4 kg/cm2 and 160°C temperature when exposed to atmosphere will

a) Boil

b) Flash i.e. Get converted into steam

c) Remain as it was

d) Cool down

Q19. The dry saturated steam at very high pressure (150-200 kg/cm2) when throttled to atmosphere will become

a) Wet

b) Superheated

c) Remain dry saturated

d) Dry

Q20. In a throttling process

a) Steam temperature remains constant

b) Steam pressure remains constant

c) Steam enthalpy remains constant

d) Steam entropy remains constant

Part 31: Objective questions and answers of Thermal Engineering