thermodynamics MCQs – Page 2

Practise focused thermodynamics questions with marked answers for exam preparation and subject revision.

thermodynamics Mcqs

21. Specific heat of air at constant pressure is equal to___________________?
0

A. 1.41

B. 0.21

C. 0.17

D. 0.24

E. 1

22. One barometric pressure or 1 atmospheric pressure is equal to___________________?
0

A. 1.0197 kgf/cm2

B. 1.033 kgf/cm2

C. 0 kgf/cm2

D. 1 kgf/cnr2

E. 100 kgf/cm2

23. For same compression ratio and for same heat added_________________?
0

A. Otto cycle is more efficient than Diesel cycle

B. Diesel cycle is more efficient than Otto cycle

C. efficiency depends on other factors

D. both Otto and Diesel cycles are equally efficient

E. none of the above

24. Which of the following processes are thermodynamically reversible___________________?
0

A. hyperbolic and pV = C

B. constant volume and constant pressure

C. throttling

D. free expansion

E. isothermal and adiabatic

25. According to Gay-Lussac law for a perfect gas, the absolute pressure of given mass varies directly as____________________?
0

A. remains constant,if volume and temperature are kept constant

B. absolute temperature, if volume is kept constant

C. volume, if temperature is kept constant

D. temperature

E. absolute

26. According to first law of thermodynamics_______________________?
0

A. mass and energy are mutually convertible

B. heat and work are mutually convertible

C. Carnot engine is most efficient

D. mass and light are mutually convertible

E. heat flows from hot substance to cold substance

27. Otto cycle consists of following four processes____________________?
0

A. two isentropics and two constant pres-sures

B. two isothermals and two isentropics

C. two isentropics and two constant volumes

D. none of the above

E. two isentropics, one constant volume and one constant pressure

28. Carnot cycle is__________________?
0

A. an adiabatic irreversible cycle

B. a quasi static cycle

C. a semi-reversible cycle

D. a reversible cycle (ft) an irreversible cycle

29. According to which law, all perfect gases change in volume by l/273th of their original volume at 0C for every 1C change in temperature when pressure remains constant ____________________?
0

A. Gay-Lussac law

B. Boyles law

C. Regnaults law

D. Joules law

E. Charles law

30. According to Avogadros Hypothesis ______________________?
0

A. the sum of partial pressure of mixture of two gases is sum of the two

B. all systems can be regarded as closed systems

C. gases have two values of specific heat

D. product of the gas constant and the molecular weight of an ideal gas is constant

E. the molecular weights of all the perfect gases occupy the same volume under same conditions of pressure and temperature

31. During throttling process___________________?
0

A. there is no change of internal energy of steam

B. entropy decreases

C. no work is done by expanding steam

D. heat exchange does not take place

E. all of the above

32. Which of the following items is not a path function ____________________?
0

A. vdp

B. kinetic energy

C. heat

D. work

E. thermal conductivity

33. Carnot cycle has maximum efficiency for__________________?
0

A. reversible engine

B. irreversible engine

C. petrol engine

D. new engine

E. diesel engine

34. The unit of energy in S.I. units is________________?
0

A. joule/s

B. joule

C. joule/m

D. joule m.

E. watt

35. I kgf/cm2 is equal to________________?
0

A. 1 mm Hg

B. lOOmmHg

C. 735.6 mm Hg

D. 760 mm Hg

E. zero mm Hg

36. An actual engine is to be designed having same efficiency as the Carnot cycle. Such a proposition is___________________?
0

A. desirable

B. possible

C. possible, but with lot of sophistications

D. impossible

E. feasible

37. The unit of power in S.I. units is_______________________?
0

A. watt

B. erg

C. newton

D. pascal

E. joule

38. The ideal efficiency of a Brayton cycle with regeneration, with increase in pressure ratio will______________?
0

A. remain unchanged

B. decrease

C. increase/decrease depending on ap-plication

D. unpredictable

E. increase

39. The unit of temperature in S.I. units is _________________?
0

A. Kelvin

B. Fahrenheit

C. Centigrade

D. Celsius

E. Rankine

40. Gas turbine cycle consists of___________________?
0

A. none of the above

B. two isentropics and two constant pressures

C. two isentropics, one constant volume and one constant pressure

D. two isentropics and two constant volumes

E. two isothermals and two isentropics

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