GATE 2019: Thermodynamics Rapid Revision Quiz for ESE & GATE ME Exams

Question 1

A petrol engine has a bore of 10 cm and a stroke of 15 cm. The work done is 1000 joules. If the clearance volume is 200 cc then the heat added(Joules) will be:

Question 2

A moist air sample has dry bulb temperature of 30 °C and specific humidity of 11.5 g water vapour per kg dry air. Assume molecular weight of air as 28.93. If the saturation vapour pressure of water at 30 °C is 5.24 kPa and the total pressure is 90 kPa, then the relative humidity (in %) of air sample is

Question 3

A heat engine operates between three thermal reservoirs. It absorbs 258 kJ of energy as heat from a reservoir at 52 °C and rejects 100 kJ and 88 kJ of energy as heat to reservoirs at 27 °C and 2 °C, respectively. It delivers 70 kJ of work. This heat engine,

Question 4

A compressor of a refrigerator is running at 250 rpm having a single cylinder compressor. The volumetric efficiency of the compressor is 90 %. Mass flow rate and specific volume at the inlet of the compressor is 0.6 Kg/s and 0.027 m3/Kg . If the diameter of the cylinder equal to length of the cylinder. Find the the diameter of the cylinder of the compressor in cm.

Question 5

Air inhalation rate of a diesel cycle is 300kg/hr with temperature and pressure 15 degree Celsius and 1.03 bar. If volumetric efficiency is 72.3%, find the swept volume flow rate.( in m³/s)

Question 6

A well insulated rigid container of volume 1m³ contains 1.0 kg of an ideal gas

at a pressure of 10⁵ Pa. A stirrer is rotated at constant rpm in the container for 1000 rotations and the applied torque is 100 N-m. The final temperature of the gas (in K) is

Question 7

A solar system at 127 °C supplies heat at a rate of 15000 kJ/hr to an absorption refrigeration system. The environment is at 27 °C and the refrigerated space is maintained at –23 °C. The maximum possible heat removal from the refrigerated space is __________ tonnes.

Question 8

Match List-I with List-II and select the correct answer using the codes given below the lists:

Question 9

A car engine operates at a fuel-air ratio of 0.05, volumetric efficiency of 90% and indicated mean effective pressure is 6 bar. If the calorific value of fuel is 45000 kJ/kg and density of air at intake is 1 kg/m³, then the indicated thermal efficiency of the cycle is ____________%.

Question 10

In order to control the temperature of steam in a steam generator, a spray type desuperheater is used. It is fed with water at 60 °C. Steam at 90 bar and 500 °C with flow rate 300 tons/hr enters the desuperheater. Neglect any pressure drop due to mixing and heat loss to the surrounding. Also given
h_g (at 90 bar and 500 °C) = 3386.1 kJ/kg
h_f (at 60 °C) = 251.11 kJ/kg
h_g (at 90 bar and 450 °C) = 3256.6 kJ/kg
Amount of water that must be sprayed to maintain steam at 450 °C, is ___________ kg/s.

Question 11

In an experimental set-up, air flows between two stations P and Q adiabatically. The direction of flow depends on the pressure and temperature conditions maintained at P and Q. The conditions at station P are 150 kPa and 350 K. The temperature at station Q is 300 K.
The following are the properties and relations pertaining to air:
Specific heat at constant pressure, c_p = 1.005 kJ/kgK;
Specific heat at constant volume, c_v = 0.718 kJ/kgK;
Characteristic gas constant, R = 0.287 kJ/kgK.
Enthalpy, h = c_pT.
Internal energy, u = c_vT.

If the air has to flow from station P to station Q, the maximum possible value of pressure in kPa at station Q is close to

Question 12

A single acting single cylinder reciprocating air compressor running at 7.5 rev/s, takes in air at 100 k Pa, 27 °C. The compressor delivers air at 600 k Pa at a flow rate of 0.12 m³/s measured at suction conditions. Given that the percentage clearance is 4 and that the index of compression and expansion is 1.2. Calculate The ideal volumetric efficiency

Question 13

What will be the change in internal energy of the system if it absorbs 2 Kcals of heat and completed 500 J of work?

Question 14

The internal energy of a certain system is a function of temperature alone and is given by formula E = 25 + 0.25 t kJ (where t is the temperature). If this system executes a process for which the work done by it per degree temperature increase is 0.75 kN-m, the heat-interaction per degree temperature increase is _________ kJ.

Question 15

A solar system at 127 °C supplies heat at a rate of 15000 kJ/hr to an absorption refrigeration system. The environment is at 27 °C and the refrigerated space is maintained at –23 °C. The maximum possible heat removal from the refrigerated space is __________ tonnes.