Thermodynamics MCQs

Question 1

In case of steady flow compression polytropic process (PV n = constant), the work done on air is the lowest, when

Accepted Answer

N = 1

Answer

N = y = 1.4

Answer

N = 0

Answer

N = 1.66

Question 2

Choose the condition that must be specified in order to liquify CO 2 (triple point for CO 2 is -57°C and 5.2 atm).

Accepted Answer

Pressure and temperature must be kept below 5.2 atm. and -57°C respectively

Answer

Pressure must be kept below 5.2 atm

Answer

Temperature must be kept above -57°C

Answer

Pressure must be kept below 5.2 atm. and temperature must be kept above 57°C

Question 3

Consider the reaction, C + O 2 ⇋ CO 2 ; ΔH = -94 kcal. What will be the value of ΔH for the reaction CO 2 → C + O 2 ?

Accepted Answer

+94 kcal

Answer

-94 kcal

Answer

> 94 kcal

Answer

< -94 kcal

Question 4

For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm 3 and that in vapour phase in 391.1 cm 3 . Fugacity of water (in kPa) at 9000 kPa will be

Accepted Answer

6753.5

Answer

6738.9

Answer

7058.3

Answer

9000

Question 5

The equation, C p - C v = R, is true for __________ gas.

Accepted Answer

Only ideal

Answer

No

Answer

Any real

Answer

Both B and C

Question 6

Efficiency of a Carnot engine working between temperatures T 1 and T 2 (T 1 < T 2 ) is

Accepted Answer

$$\frac{{{{	ext{T}}_2} - {{	ext{T}}_1}}}{{{{	ext{T}}_2}}}$$

Answer

$$\frac{{{{	ext{T}}_2} - {{	ext{T}}_1}}}{{{{	ext{T}}_1}}}$$

Answer

$$\frac{{{{	ext{T}}_1} - {{	ext{T}}_2}}}{{{{	ext{T}}_2}}}$$

Answer

$$\frac{{{{	ext{T}}_1} - {{	ext{T}}_2}}}{{{{	ext{T}}_1}}}$$

Question 7

Co-efficient of performance for a reversed Carnot cycle working between temperatures T 1 and T 2 (T 1 > T 2 ) is

Accepted Answer

$$\frac{{{{	ext{T}}_2}}}{{{{	ext{T}}_1} - {{	ext{T}}_2}}}$$

Answer

$$\frac{{{{	ext{T}}_1}}}{{{{	ext{T}}_1} - {{	ext{T}}_2}}}$$

Answer

$$\frac{{{{	ext{T}}_1} - {{	ext{T}}_2}}}{{{{	ext{T}}_1}}}$$

Answer

$$\frac{{{{	ext{T}}_1} - {{	ext{T}}_2}}}{{{{	ext{T}}_2}}}$$

Question 8

In the equation, PV n = Constant, if the value of n = 0, then it represents a reversible __________ process.

Accepted Answer

Isobaric

Answer

Isothermal

Answer

Isentropic

Answer

Isometric

Question 9

In the equation, PV n = constant, if the value of n = 1, then it represents a reversible __________ process.

Accepted Answer

Isothermal

Answer

Isobaric

Answer

Polytropic

Answer

Adiabatic