GATE ME Applications PYQs & Answers — Page 2

Questions 11–20 of 61. Imported answers require independent review unless marked reviewed.

A heat pump (H.P.) is driven by the work output of a heat engine (H.E.) as shown in the figure. The heat engine extracts 150 kJ of heat from the source at 1000 K. The heat pump absorbs heat from the ambient at 280 K and delivers heat to the room which is maintained at 300 K. Considering the combined system to be ideal, the total amount of heat delivered to the room together by the heat engine and heat pump is ______kJ (answer in integer).

Diagram for Mechanical Engineering question 47

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Consider a steady flow through a horizontal divergent channel, as shown in the figure, with supersonic flow at the inlet. The direction of flow is from left to right.

Diagram for Mechanical Engineering question 24

Pressure at location B is observed to be higher than that at an upstream location A. Which among the following options can be the reason?

Your answerChoose one option.

Since volume flow rate is constant, velocity at B is lower than velocity at A

Normal shock

Viscous effect

Boundary layer separation

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The figure shows a purely convergent nozzle with a steady, inviscid compressible flow of an ideal gas with constant thermophysical properties operating under choked condition. The exit plane shown in the figure is located in the nozzle. If the inlet pressure (

) is increased while keeping the back pressure (

) unchanged, which of the following statements is/are true?

Diagram for Mechanical Engineering question 30

Your answerSelect all correct options. You can choose more than one.

Mass flow rate through the nozzle will remain unchanged.

Mach number at the exit plane of the nozzle will remain unchanged at unity.

Mass flow rate through the nozzle will increase.

Mach number at the exit plane of the nozzle will become more than unity.

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In a vapour compression refrigeration cycle, the refrigerant enters the compressor in saturated vapour state at evaporator pressure, with specific enthalpy equal to 250 kJ/kg. The exit of the compressor is superheated at condenser pressure with specific enthalpy equal to 300 kJ/kg. At the condenser exit, the refrigerant is throttled to the evaporator pressure. The coefficient of performance (COP) of the cycle is 3. If the specific enthalpy of the saturated liquid at evaporator pressure is 50 kJ/kg, then the dryness fraction of the refrigerant at entry to evaporator is __________.

Your answerChoose one option.

0.2

0.25

0.3

0.35

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In a steam power plant based on Rankine cycle, steam is initially expanded in a high-pressure turbine. The steam is then reheated in a reheater and finally expanded in a low-pressure turbine. The expansion work in the high-pressure turbine is 400 kJ/kg and in the low-pressure turbine is 850 kJ/kg, whereas the pump work is 15 kJ/kg. If the cycle efficiency is 32%, the heat rejected in the condenser is ________ kJ/kg (round off to 2 decimal places).

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At steady state, 500 kg/s of steam enters a turbine with specific enthalpy equal to 3500 kJ/kg and specific entropy equal to 6.5 kJ·kg⁻¹·K⁻¹. It expands reversibly in the turbine to the condenser pressure. Heat loss occurs reversibly in the turbine at a temperature of 500 K. If the exit specific enthalpy and specific entropy are 2500 kJ/kg and 6.3 kJ·kg⁻¹·K⁻¹, respectively, the work output from the turbine is ________ MW (in integer).

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An engine running on an air standard Otto cycle has a displacement volume 250 cm

and a clearance volume 35.7 cm

. The pressure and temperature at the beginning of the compression process are 100 kPa and 300 K, respectively. Heat transfer during constant-volume heat addition process is 800 kJ/kg. The specific heat at constant volume is 0.718 kJ/kg.K and the ratio of specific heats at constant pressure and constant volume is 1.4. Assume the specific heats to remain constant during the cycle. The maximum pressure in the cycle is ______ kPa (round off to the nearest integer).

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In which of the following pairs of cycles, both cycles have at least one isothermal process?

Your answerChoose one option.

Diesel cycle and Otto cycle

Carnot cycle and Stirling cycle

Brayton cycle and Rankine cycle

Bell-Coleman cycle and Vapour compression refrigeration cycle

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The relative humidity of ambient air at 300 K is 50% with a partial pressure of water vapour equal to

. The saturation pressure of water at 300 K is

. The correct relation for the air-water mixture is

Your answerChoose one option.

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Consider adiabatic flow of air through a duct. At a given point in the duct, velocity of air is 300 m/s, temperature is 330 K and pressure is 180 kPa. Assume that the air behaves as a perfect gas with constant

kJ/kg.K. The stagnation temperature at this point is ______ K (round off to two decimal places).

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GATE ME Applications PYQs

Question 47

Question 24

Question 30

Question 45

Question 61

Question 61

Question 62

Question 11

Question 15

Question 20