MCQs Mechanical Engineering
1. The latent heat of steam with increase in pressure
(a) does not change
(b) increases
(c ) decrease
(d) remains unpredictable
Ans. C
2. Steam coming out of the whistle of a pressure cooker is
(a) dry saturated vapour
(b)wet vapour
(c ) super heated vapour
(d) ideal gas
Ans. B
3. At critical point, any substance
(a) will exist in all the three phases simultaneously
(b) will change directly from solid to vapour
(c )will lose phase distinction between liquid and vapour
(d)will behave as in ideal gas
Ans. C
4. Dry ice is
(a) solidified carbon dioxide
(b) ice free from dissolved air and gases
(c ) ice from from impurities
(d) ice made from transparent distilled water
Ans. A
5. The ratio of two specific heats of air is equal
(a) 0.17
(b) 0.24
(c )0.1
(d)1.41
Ans. D
6. Triple point of a pure substance is a point at which
(a) liquid and vapour exist together
(b) solid and liquid exist together
(c )solid and vapour exist together
(d)solid , liquid and vapour phase exist together
Ans. D
7. Triple point and critical point pressure of carbon dioxide are
(a)4.58 mm Hg and 221.2 bar respectively
(b)5.18 bar and 221.2 bar respectively
(c )1 bar and 50 bar respectively
(d) 5.18 and 73.8 bar respectively
Ans. D
8. Sensible heat is the heat needed to
(a ) Vaporise water into steam and vice versa
(b) Change the temperature of a liquid or vapoure
(c )Convert water into steam and super heat it
(d) Measure dew point temperature
Ans. B
9. Dry ice is :
(a) free from water
(b) free from dissolved air or gases
(c )does not contain impurities
(d)solidified from of carbon dioxide
Ans. D
10. If ha is enthalpy of dry air , hv is enthalpy of water vapour and w is speecific humidity , the enthalpy of moist air will b
(a) ha + hv
(b) ha + whv
(c ) hv+ wha
(d) hv +ha/w
Ans. B
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