SECTION-3

##### Q31. Adiabatic expansion of a gas is given by the law

(a) pV = constant
(b) pVγ = constant
(c) pV0 = constant
(d) pV∞ = constant.

Ans:(b) pVγ = constant

##### Q32. The difference between free expansion and throttling is

(a) enthalpy is constant in free expansion but not in throttling
(b) temperature is constant in free expansion but not in throttling
(c) that is case of free expansion the work done is zero but in case of throttling work done is not zero.
(d) that in case of free expension the gas leaves with large velocity where as in throttling the gas has negligible velocity.

Ans:(d) that in case of free expension the gas leaves with large velocity where as in throttling the gas has negligible velocity.

(a) 45°C
(b) 100°C
(c) 177°C
(d) 330°C.

Ans:(c) 177°C

##### Q34. In case of hyperbolic expansion of a gas, heat supplied is

(a) more than the work done
(b) less than the work done
(c) equal to the work done
(d) none of the above.

Ans:(c) equal to the work done

##### Q35. In heat units, the value of universal gas constant is equal to

(a) 19.86 kcal/kg mole/K
(b) 1.986 kcal/kg mole/K
(c) 198.6 kcal/kg mole/K
(d) none of the above.

Ans:(b) 1.986 kcal/kg mole/K

##### Q36. The heat supplied at constant volume for a non-flow process is

(a) mCp [T2 – T1
(b) mCv(T2 – T1
(c) mCp[T2 + T1
(d) mCv(T2 + T1

Ans:(b) mCv(T2 – T1)

##### Q37. The heat supplied to a gas at constant pressure for a non-flow process is

(a) mCp [T2 – T1
(b) mCv(T2 – T1
(c) mCp[T2 + T1
(d) mCv(T2 + T1

Ans:(a) mCp [T2 – T1]

##### Q38. One kg mole of a gas is equal to

(a) molecular weight of the gas
(b) atomic weight
(c) mass of a gas of volume 22.41 m3 at N.T.P
(d) none of the above.

Ans:(a) molecular weight of the gas

##### Q39. The value of gas constant for air in M.K.S. units is equal to

(a) 287 kgf-m/kg/K
(b) 28.7 kgf-m/kg/K
(c) 29.27 kgf-m/kg/K
(d) 87.2 kgf-m/kg/K

Ans:(c) 29.27 kgf-m/kg/K

##### Q40. The value of gas constant for air in S.I. units is equal to

(a) 287 N m/kg/K
(b) 28.7 Nm/kg/K
(c) 29.27 kgf m/kg/K
(d) 0.287 J/kg/K

Ans:(a) 287 N m/kg/K

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##### Read More Sections of Thermodynamics Objective Questions

Each section contains maximum 80 Questions. To practice more questions visit other sections.

Thermodynamics Objective Questions – Section-1

Thermodynamics Objective Questions – Section-2

Thermodynamics Objective Questions – Section-3

Thermodynamics Objective Questions – Section-4