GATE XE year:2017 PYQs & Answers — Page 9

Questions 81–90 of 175. Imported answers require independent review unless marked reviewed.

A refrigerator is used to maintain certain space at 10°C. It pumps 18000 kJ/hour of heat from the space to the atmosphere at 30°C. If the power input to the refrigerator is 2 kW, the ratio of COP of this refrigerator to that of a Carnot refrigerator (up to 2 decimal places) is ________.

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A thermal cycle receives 200 kJ of heat from a heat source at 1000 K. It rejects 300 kJ of heat to a heat sink at 300 K and also rejects 250 kJ of heat to another heat sink at 200 K during the cycle. The cycle is

Your answerChoose one option.

reversible

irreversible

impossible

work absorbing

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Saturated liquid water is slowly heated at a constant pressure of 200 kPa to a final state where its quality reaches 0.65. For water at 200 kPa:

°C,

kJ/kg,

kJ/kg. The change in the specific entropy in kJ/kg.K is

Your answerChoose one option.

3.04

3.24

3.44

3.64

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Given the thermodynamic function relations:

and

, the term

is equal to

Your answerChoose one option.

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Two closed cycle gas turbine engines, A and B, operate on air standard Brayton cycle with efficiencies of

and

, respectively. If they operate between the same maximum and minimum temperatures, but with different pressure ratios of

and

, (

), then,

Your answerChoose one option.

cannot be determined as the efficiencies are maximum only at the optimal

values.

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The values of density and isentropic compressibility of water at certain pressure and temperature are given as 1000 kg/m³ and

Pa⁻¹, respectively. The speed at which sound travels in water under these conditions in m/s is equal to ________.

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Length of a certain metal rod at 0°C is 10 cm. The coefficient of linear expansion of that metal varies with temperature as

(cm/cm)/°C. When the length of the metal rod is 10.2 cm, the rise in temperature in °C is ________.

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In a polytropic compression process, one kg of an ideal gas having a molecular weight of 40 kg/kmol is compressed from 100 kPa, 300 K to 400 kPa, 360 K. The magnitude of the work in kJ for the process is

Your answerChoose one option.

52.3

62.3

72.3

82.3

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Two streams of air (

J/kg.K) flow through insulated pipes 1 and 2 with the conditions as shown in figure. They mix in an insulated pipe-3 and the mixture steadily exits with a velocity of 100 m/s at 150 kPa. Neglecting the change in potential energy in all the pipes, the exit area of the pipe-3 in m² (up to 3 decimal places) is ________.

Diagram for Engineering Sciences question 89

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A 1 m³ rigid vessel contains air at 200 kPa. A vacuum pump is connected to the vessel in order to control the pressure inside. The volume flow rate of air through the pump is maintained at a constant value of 0.1 m³/s. If the pump operates for 10 seconds and the temperature of the air is maintained constant during operation, the pressure in the tank in kPa after 10 seconds (up to 2 decimal places) is ________.

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GATE XE year:2017 PYQs

Question 81

Question 82

Question 83

Question 84

Question 85

Question 86

Question 87

Question 88

Question 89

Question 90