# Thermodynamics – Section 1

31. Which of the following gas is mostly used in town for street and domestic lighting and heating?

A. Producer gas
B. Coal gas
C. Mond gas
D. Coke oven gas

32. The value of the gas constant (R) in S. I. units is

A. 0.287 J/kgK
B. 2.87 J/kgK
C. 28.7 J/kgK
D. 287 J/kgK

33. In the first law of thermodynamics, the total energy of the system remains constant.

A. True
B. False

34. The efficiency of the Diesel cycle increases with

A. decrease in cut-off
B. increase in cut-off
C. constant cut-off
D. none of these

Correct Answer: A. decrease in cut-off

35. Coal gas is obtained by mixing coal and gas at ambient conditions.

A. Yes
B. No

36. According to Avogadro’s law, the density of any two gases is __________ their molecular masses, if the gases are at the same temperature and pressure.

A. equal to
B. directly proportional to
C. inversely proportional to

Correct Answer: B. directly proportional to

37. The kinetic energy of molecules of a gas becomes zero at absolute zero temperature.

A. Agree
B. Disagree

38. One kg of carbon monoxide requires __________ kg of oxygen to produce 11/7 kg of carbon dioxide gas.

A. All
B. 4/7
C. 11/4
D. 9/7

39. The absolute zero temperature is taken as

A. -273°C
B. 273°C
C. 237°F
D. -237°F