GATE ME 1. Thermodynamics Chapter Thermodynamics Test

Question 1
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A single fixed point temperature scale is based on

A
Ice point

B
Steam point

C
Triple point of water

D
Critical point of water

Question 2
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A piston cylinder contains air at 600 kPa, 290 K and a volume of 0.01m³. A constant pressure process gives 54 kJ of work out. Find the final volume of the air.

A
0.05 m³

B
0.01 m³

C
0.10 m³

D
0.15 m³

Question 3
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A fan is used to deliver air at the rate of 5 m³/s with a velocity of 10 m/s. Find the power in Watts that must be supplied to the fan. Density of air = 1.2 kg/m³.

A
299.5-300.5

B
299.54-300.51

C
299.57-300.56

D
299.59-300.52

Question 4
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A cylinder contains 5 m³of ideal gas at a pressure of 1 bar. This gas is compressed in a reversible isothermal process till its pressure increases to 5 bar. The work in kJ required for this process is

A
804.7

B
953.2

C
981.7

D
1012.2

Question 5
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One reversible heat engine operates between 1000 K and T₂K and another reversible heat engine operates between T₂K and 400 K. If both the engines have the same heat input and output, then the temperature T₂ must be equal to:

A
582.7 K

B
632.5 K

C
682.8 K

D
732.5 K

Question 6
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Directions For Questions

When a system is taken from state A to state B along the path A-C-B, 180 kJ of heat flows into the system and it does 130 kJ of work (see figure given):

...view full instructions

How much heat will flow into the system along the path A-D-B if the work done by it along the path is 40 kJ?

A
40 kJ

B
60 kJ

C
90 kJ

D
135 kJ

Question 7
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Two air streams with mass flow rates of 36 kg/min and 14 kg/min with respective enthalpies of 36 kJ/kg da and 50 kJ/kg da are mixed. The enthalpy of the mixture is nearly

A
64 kJ/kg da

B
55 kJ/kg da

C
46 kJ/kg da

D
40 kJ/kg da

Question 8
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A 20 kg solid whose specific heat is 2.8 kJ/kg°C is at uniform temperature of 100°C. For an environment temperature of 20°C the exergy content of this solid in kJ is

A
518-525

B
5184-5251

C
5187-5256

D
5189-5252

Question 9
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The thermal efficiency of the hypothetical cycle shown is

A
0.6

B
0.5

C
0.4

D
0.3

Question 10
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Which one of the following relationships defines the Helmholtz function F?

A
F = H + TS

B
F = H – TS

C
F = U – TS

D
F = U + TV

Question 11
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A 1 m³ rigid tank contains 10 kg of water (in any phase or phases) at 160°C. The pressure in the tank is
(steam table is given below)
Temperature
(°C)
Saturation Pressure
(kPa)
Specific volume
m³/kg
v_f
v_g
160
618
0.001102
0.3068

A
Equal to 618 kPa

B
Greater than 618 kPa

C
Less than 618 kPa

D
Not possible to determine with the given data

Question 12
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If the work done on a closed system is 20 kJ/kg, and 40 kJ/kg heat is rejected from the system, change in internal energy is

A
20 kJ/kg

B
60 kJ/kg

C
-20 kJ/kg

D
-60 kJ/kg

Question 13
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85 kJ of heat is supplied to a closed system at constant volume. During the next process, the system rejects 90 kJ of heat at constant pressure while 20 kJ of work is done on it. The system is brought to the original state by an adiabatic process. The initial internal energy is 100 kJ. Then what is the quantity of work transfer during the process?

A
30 kJ

B
25 kJ

C
20 kJ

D
15 kJ

Question 14
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A balloon containing an ideal gas is initially kept in an evacuated and insulated room. The balloon ruptures and the gas fills up the entire room. Which one of the following statements is TRUE at the end of above process ?

A
The internal energy of the gas decreases from its initial value, but the enthalpy remains constant

B
The internal energy of the gas increases from its initial value, but the enthalpy remains constant

C
Both internal energy and enthalpy of the gas remain constant

D
Both internal energy and enthalpy of the gas increase

Question 15
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For a simple closed system of constant composition, the difference between the net heat and work interactions is identifiable as the change in

A
Enthalpy

B
Entropy

C
Flow energy

D
Internal energy

Question 16
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A 2 m³ rigid tank contains 50 kg of steam at 240°C. Find the dryness fraction of the steam in the tank and the volume of the gaseous steam in m³in the tank. Properties of the steam at 240°C and 33.44 bar is given in the table below.

T_sat

v_f

v_g

240°C

0.0012 m³/kg

0.06 m³/kg

A
0.33 and 0.03 m³

B
0.66 and 1.98 m³

C
0.5 and 0.02 m³

D
0.66 and 1.02 m³

Question 17
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Directions For Questions

The values of heat transfer and work transfer for four processes of a thermodynamic cycle are given below:

...view full instructions

The thermal efficiency and work ratio for the cycle will be respectively.

A
33% and 0.66

B
66% and 0.36.

C
36% and 0.66

D
33% and 0.36.

Question 18

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A mixture of gas has following composition by the mass

gas	Mass %	C_p (kJ/kg.K)	C_v (kJ/kg.K)
1	50	1.2	0.9
2	30	1.5	1
3	20	1.3	1.1

Find the ratio of the specific heats (C_p/C_v) of the mixture _____ up to three decimal places.

1.34-1.36

1.344-1.361

1.347-1.366

1.349-1.362

Question 19
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The contents of a well-insulated tank are heated by a resistor of 23 ohm in which 10 A current is flowing. Consider the tank along with its contents as a thermodynamic system. The work done by the system and the heat transfer to the system are positive. The rates of heat (Q), work (W) and change in internal energy (ΔU) during the process in kW are

A
Q = 0,W =-2.3,ΔU = +2.3

B
Q=+2.3, W = 0, ΔU = +2.3

C
Q = -2.3, W = 0, ΔU = -2.3

D
Q = 0, W = +2.3, ΔU = -2.3

Question 20
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The saturation temperature of water is given as 200°C at 15.54 bar. The properties of the water vapour is given in the table below,
Temperature
(°C)
Saturation Pressure
(bar)
Specific volume
m3/kg
Specific enthalpy
kJ/kg
vf
vg
hf hg
200
15.54
0.001156
0.12736
852.43 2793.2
then find ou the value of \({\left( {\frac{{dP}}{{dT}}} \right)_{sat}} \)in kPa/K

A
32.51 kPa/K

B
76.88 kPa/K

C
35.43 kPa/K

D
15.378 kPa/K

Question 21
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Directions For Questions

The following four figures have been drawn to represent a fictitious thermodynamic cycle, on the p-v and T-s planes.

...view full instructions

According to the first law of thermodynamics, equal areas are enclosed by

A
Figures 1 and 2

B
Figures 1 and 3

C
Figures 1 and 4

D
Figures 2 and 3

Question 22
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Directions For Questions

The inlet and the outlet conditions of steam for an adiabatic steam turbine are as indicated in the figure. The notations are as usually followed.

...view full instructions

If mass flow rate of steam through the turbine is 20 kg/s the power output of the turbine (in MW) is:

A
12.157

B
12.941

C
168.001

D
168.785

Question 23
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Which one of the following expresses the reversible work done by the system (steady flow) between states 1 and 2?

A

B

C

D

Question 24
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A reversible heat engine receives 400 kJ and 300 kJ of heat from two thermal reservoirs at 800 K and 600 K respectively. It rejects heat to a reservoir at 300 K. The percent efficiency of the engine is_________

A
56-59

B
564-591

C
567-596

D
569-592

Question 25
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The gas entering in the turbine chamber of a gas turbine has the temperature of 1300 K, the turbine is insulated and the work done by the turbine is 1 MJ/kg of the mass of the gas if the change in kinetic and potential energy (Inlet – Outlet) is 2 kJ/kg and 1 kJ/kg respectively then the exit temperature of the gas is____K, if specific heat of the gas at constant pressure is 1.005 kJ/kg.K.

A
307-309

B
3074-3091

C
3077-3096

D
3079-3092

Submit Test

T_sat	v_f	v_g
240°C	0.0012 m³/kg	0.06 m³/kg

Thermodynamics ...

Question 1

Ice point

Steam point

Triple point of water

Critical point of water

Question 2

0.05 m3

0.01 m3

0.10 m3

0.15 m3

Question 3

299.5-300.5

299.54-300.51

299.57-300.56

299.59-300.52

Question 4

804.7

953.2

981.7

1012.2

Question 5

582.7 K

632.5 K

682.8 K

732.5 K

Question 6

40 kJ

60 kJ

90 kJ

135 kJ

Question 7

64 kJ/kg da

55 kJ/kg da

46 kJ/kg da

40 kJ/kg da

Question 8

518-525

5184-5251

5187-5256

5189-5252

Question 9

0.6

0.5

0.4

0.3

Question 10

F = H + TS

F = H – TS

F = U – TS

F = U + TV

Question 11

Equal to 618 kPa

Greater than 618 kPa

Less than 618 kPa

Not possible to determine with the given data

Question 12

20 kJ/kg

60 kJ/kg

-20 kJ/kg

-60 kJ/kg

Question 13

30 kJ

25 kJ

20 kJ

15 kJ

Question 14

The internal energy of the gas decreases from its initial value, but the enthalpy remains constant

The internal energy of the gas increases from its initial value, but the enthalpy remains constant

Both internal energy and enthalpy of the gas remain constant

Both internal energy and enthalpy of the gas increase

Question 15

Enthalpy

Entropy

Flow energy

Internal energy

Question 16

0.33 and 0.03 m3

0.66 and 1.98 m3

0.5 and 0.02 m3

0.05 m³

0.01 m³

0.10 m³

0.15 m³

0.33 and 0.03 m³

0.66 and 1.98 m³

0.5 and 0.02 m³

0.66 and 1.02 m³