ESE ME Thermal Science : National Champion Test for ESE & GATE ME Exams

Question 1

Air is being forced by the bicycle pump into a tyre against a pressure of 4.5 bars. A slow downward movement of the piston can be approximated as

Question 2

One kg of ice at 0⁰ C is completely melted into water at 0⁰ C at 1 bar pressure. The latent heat of fusion of water is 333 kJ/kg and the densities of water and ice at 0⁰C are 999.0 kg/m³ and 916.0 kg/m³, respectively. What are the approximate values of the work done and energy transferred as heat for the process, respectively?

Question 3

In a reversible isothermal expansion process, the fluid expands from 10 bar and 2 m³ to 2 bar and 10 m³, during the process the heat supplied is 100 kW. The work done during the process is

Question 4

A 4 kW, 20 litre water heater is switched on for 10 minutes. The heat capacity C_p for water is 4 kJ/kg k. Assuming all the electrical energy has gone into heating the water. The increase of the water temperature is

Question 5

Which one of the following statements is correct when saturation pressure of water vapour increases?

Question 6

For a pure substance, what are the numbers of the thermodynamic degrees of freedom for saturated vapour and superheated vapour, respectively?

Question 7

The thermal efficiency of a Carnot heat engine is 30%. If the engine is reversed in operation to work as a heat pump with operating conditions unchanged, then what will be the COP for heat pump?

Question 8

A refrigeration unit has a COP of 4 and extracts 10 kJ of heat from the cold reservoir. If this machine works as a heat pump, how much heat will it deliver to the environment?

Question 9

An amount of 1000 kJ of heat is added to a system during a constant pressure vapourization process at a temperature of

. The available energy added to the system, if the temperature of the surroundings is

, is

Question 10

Which thermodynamics property is evaluated with the help of Maxwell equation from equations from the data of other measurable properties of a system?

Question 11

A positive value of Joule-Thomson coefficient of a fluid means

Question 12

Assertion (A) : When the surface of a lake is cooled during winter the cooled surface water descends to the bottom as long as its temperature exceeds 4⁰ C , but when cooled below 4⁰ c it floats at the top.
Reason (R) : Ice forms at the top of a pond in winter while bottom fluid stays warmer at more than 4⁰ C.

Question 13

Statement (I) : Negative temperature are impossible on the Kelvin scale.
Statement (II) : The Kelvin scale is the thermodynamic temperature scale.

Question 14

In an engine working on air standard Stirling cycle the temperature of isothermal compression is 127 °C. The engine thermal efficiency is 50%. The specific heat of air at constant volume is C_P. The heat transferred to the regenerator is

Question 15

Assertion (A): The cut off ratio of a Diesel engine cycle should be greater than one, but should be as low as possible.
Reason (R): Lower cut off ratio does improve the thermal efficiency but lowers the specific work output. Hence, the value of cut off ratio must be optimized.

Question 16

A condenser of a refrigeration, system rejects heat at a rate of 120 kW, while the compressor of the system consumes a power of 30 kW. The COP of the system will be

Question 17

In a VCRS plant, the refrigerant leaves the compressor and evaporator with enthalpy of 205 kJ/kg and 177 kJ/kg respectively. Enthalpy of the refrigerant leaving the condenser is 105 kJ/kg. If the mass flow rate of the refrigterant is 0.2 kg/s, the refrigeration effect will be

Question 18

An air-conditioning system operating on the reversed Carnot cycle is required to remove neat from the room at a rate of 25 kW to maintain its temperature constant at 20^oC. The temperature of the surroundings being 35^oC, the power required to operate this air-conditioning system will be

Question 19

For an air-conditioned space, RTH = 100 kW, RSHF = 0.75, volume flow rate = 100 m³/min, and indoor design specific humidity is 0.01 kg/kg of dry air. What is the specific humidity of the supply air (in kg/kg of dry air)______?

Question 20

In a Brayton cycle, the value of optimum pressure ratio for maximum net work done between temperatures T₁ and T₃, where T₃ is the maximum temperature and T₁ is the minimum temperature is

Question 21

An open cycle constant pressure gas turbine uses a fuel of calorific value 40,000 kj/kg, with air fuel ratio of 80:1 and develops a net output of 80kj/kg of air. The thermal efficiency of the cycle is

Question 22

For a 2-stage air compressor for the maximum efficiency of compressor, consider the following statements:
1)

2)

3) Intercooling between the stages is complete
4) Work is equally shared by the two stages
Which of these statements are correct?

Question 23

Statement (I): The index of compression and the index of expansion are different in reciprocating compressors.
Statement (II): Reciprocating compressors are used to compress a large pressure ratio and low discharge.

Question 24

Reheating of steam in a steam power plant:
1) Increases the cycle efficiency
2) Reduces the turbine speed
3) Reduces blade erosion
4) Increases specific output
Which of above statements are correct?

Question 25

A power plant, which uses a gas turbine followed by steam turbine for power generation, is called