TITLE.PM5

218 ENGINEERING THERMODYNAMICS

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/M-therm/Th4-7.pm5

16. The processes or systems that do not involve heat are called
    (a) isothermal processes (b) equilibrium processes
    (c) thermal processes (d) steady processes
    (e) adiabatic processes.


17. In a reversible adiabatic process the ratio (T 1 /T 2 ) is equal to

(a) pp^1

2

1

F

HG

I

KJ

−γ

γ (b) v

v

1

2

1

F

HG

I

KJ

−γ

γ

(c) vv 12

1

bg 2

γ

γ

−

.(d)FHGvv 12 IKJ

γ

.

18. In isothermal process
    (a) temperature increases gradually (b) volume remains constant
    (c) pressure remains constant (d) enthalpy change is maximum
    (e) change in internal energy is zero.


19. During throttling process
    (a) internal energy does not change (b) pressure does not change
    (c) entropy does not change (d) enthalpy does not change
    (e) volume change is negligible.


20. When a gas is to be stored, the type of compression that would be ideal is
    (a) isothermal (b) adiabatic
    (c) polytropic (d) constant volume
    (e) none of the above.


21. If a process can be stopped at any stage and reversed so that the system and surroundings are exactly
    restored to their initial states, it is known as
    (a) adiabatic process (b) isothermal process
    (c) ideal process (d) frictionless process
    (e) energyless process.


22. The state of a substance whose evaporation from its liquid state is complete, is known as
    (a) vapour (b) perfect gas
    (c) air (d) steam.


23. In SI units, the value of the universal gas constant is
    (a) 0.8314 J/mole/K (b) 8.314 J/mole/K
    (c) 83.14 J/mole/K (d) 831.4 J/mole/K
    (e) 8314 J/mole/K.


24. When the gas is heated at constant pressure, the heat supplied
    (a) increases the internal energy of the gas (b) increases the temperature of the gas
    (c) does some external work during expansion (d) both (b) and (c)
    (e) none of the above.


25. The gas constant (R) is equal to the
    (a) sum of two specific heats (b) difference of two specific heats
    (c) product of two specific heats (d) ratio of two specific heats.


26. The heat absorbed or rejected during a polytropic process is

(a)

γ

γ

−

−

F

HG

I

KJ

n

1 × work done (b)

γ

γ

−

−

F

HG

I

KJ

n

1

2

× work done

(c) γ

γ

−

−

F

HG

I

KJ

n

1

1/ 2

× work done (d)GHFγγ−−n 1 IKJ

3

× work done.