Steam Boiler and Engines mcq

Steam Boiler and Engines mcq

1. The state of vapor under saturation condition is

described by

pressure and dryness fraction.

2. Water boils when its vapour pressure

equals that of the surroundings.

3. Mechanical equivalent of heat for 1 kcal or Joule’s equivalent is equal to

421 kgm.

4. Equivalent evaporation of water is the evaporation

“for a feed water supply at 100°C

and its corresponding conversion into dry saturated steam at 100°C and 1.033 kg/cm².

5. The evaporation of 15.653 kg of water per hour from and at 100°C is called

one boiler h.p.

6. The increase in pressure

raises the boiling point of a liquid

7. During polytropic process

(a) heat transfer takes place across cylinder walls

(b) work is done

(c) steam may be wet, dry or super-heated after

expansion

(d) all the above.

8. Hygrometer deals with the

water vapour in air.

9. 1 kg. M is equal to

9.81 Joules.

10. Equivalent evaporation is the amount of water

evaporated in a boiler from and at

100°C.

11. The specific volume of steam with increase in

pressure decreases

rapidly first and then slowly.

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

any type of boilers operating under any conditions.

13. The coal requirement per kW hour generation in the thermal power plant is of the order of

0.6 to 0.8 kg.

14. Sublimation region is the region where

solid and vapour phases are in equilibrium.

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

Superheated.

16. Water at pressure of 4 kg/cm2 and 160°C

temperature when exposed to atmosphere will

flash i.e. get converted into steam.

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

 Wet.

18. In a throttling process

steam enthalpy remains constant.

19. The pressure at which latent heat of vaporization of water is zero, is

225.6 kg/cm².

20. Latent heat of dry steam at atmospheric pressure is equal to

539 kcal/kg.

21. The latent heat of steam with increase of pressure

Decreases.

22. Stoichiometric quantity of air is the

air required for complete combustion of fuel with no excess air.

23. One kg of steam sample contains 0.8 kg dry steam it’s dryness fraction is

0.8.

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

throttling calorimeter.

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

0.5

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