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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on Thermodynamics Set 10

Q1 | The efficiency of a Rankine cycle may be expected to
  • Increase with decreasing temperature of heat rejection
  • Decrease with decreasing temperature of heat rejection
  • Decrease with increasing temperature of heat rejection
  • Increase with increasing exhaust pressure
  • None of the above
Q2 | A heat engine works on a Carnot cycle with a heat sink at a temperature of 27?C. The efficiency of the engine is 10%, the temperature of the heat source is
  • 30?C
  • 270?C
  • Temperature shows the extent of expansion
  • 60?C
  • 10?C
Q3 | All of the following cycles consist of two isentropic processes EXCEPT
  • Otto cycle
  • Stirling cycle
  • Pulsejet
  • Carnot cycle
  • Diesel cycle
Q4 | 1 micron is equivalent to
  • 10-2 cm
  • 10-3 cm
  • 10-4 cm
  • 10-6 cm
  • None of the above
Q5 | A system consisting of more than one phase is known as
  • Isolated system
  • Closed system
  • Non-uniform system
  • Open system
  • Heterogeneous system
Q6 | In which case the work done per kg of air compressed from 1.05 ata, 15?C to 6.3 ata is minimum
  • Polytropic with index n = 1.35
  • Adiabatic
  • Polytropic with index n = 1.40
  • Isothermal
  • Polytropic with index n = 1.3
Q7 | Thermei is
  • A semi-conductor
  • An impurity added to a semi-conductor
  • A unit of temperature measurement
  • A unit of latent heat
  • Quantity of heat required to raise temperature of one tonne of water from 14.5?C to 15.5?C
Q8 | Heat flows from hot substance to cold substance unaided". The name associated with the above statement is
  • Gay Lussac
  • Joule
  • Clausius
  • Planck
  • Kelvin
Q9 | The concept of black body in heat transfers applies to
  • microns
  • Objects which are black in colour
  • Objects well insulated from surroundings
  • Objects which are good conductors of heat
  • Objects that completely absorb impinging radiation
Q10 | A solar cell system is to suppmy 1050 kWh/month. The average output is 15 percent of the rated power. The rated power must be
  • 4.5 kW
  • Pulsejet
  • 9.7 kW
  • 3 kW
  • 14.4 kW
Q11 | Most of gases exhibit drop in temperature upon expansion. However, this may not be true in case of
  • Carbondioxide
  • Hydrogen
  • Helium
  • Oxygen
  • Pulsejet
Q12 | The extension and compression of a helical spring is an example of
  • Reversible process
  • Adiabatic process
  • Thermodynamic cycle
  • Irreversible process
  • Isothermal process
Q13 | In a Carnot cycle if isothermal compression process is continued bit longer than the normal, then the adiabatic compression will cause the steam to arrive at the inner dead center at a temperature
  • higher than the normal temperature
  • lower than the normal temperature
  • which is the normal temperature
  • Pulsejet
Q14 | Which of the following cycle consists of two constant pressure and two adiabatic processes?
  • Carnot cycle
  • Joule cycle
  • Diesel cycle
  • Dual cycle
  • Otto cycle
Q15 | One litre of gas A and two litres of gas B. both having same temperature 100?C and same pressure 2.5 bar will have the ratio of kinetic energies of their molecules as
  • 1 ; 2
  • 4 ; 1
  • 1 ; 1
  • 1 ; 4
  • Pulsejet
Q16 | Diesel cycle processes are
  • Two isentropic, one constant volume one constant pressure
  • Isentropic, isothermal, constant volume, constant pressure
  • Two constant volume, one constant pressure, one isothermal
  • Two isentropic and two isothermal
  • Two constant pressure, one constant volume, one isentropic
Q17 | Which of the following cycle is less efficient than the remaining?
  • Ericsson cycle
  • Stirling cycle
  • Otto cycle
  • Pulsejet
  • Carnot cycle
Q18 | The function of a clutch in automobiles
  • To disengage power from engine to flywheel
  • To disengage power from engine to gear box
  • To disengage power from engine to wheels
  • To absorb power
  • To disengage power from wheels to engine
Q19 | The rate of heat flow from a 50 mm thick wall of material having thermal conductivity of 40 W/m?C for a temperature difference of 10?C will be
  • 80000 kcal/m2 hr
  • 800 kcal/m2 hr
  • 2000 kcal/m2 hr
  • 8000 kcal/m2 hr
  • 80 kcal/m2 hr
Q20 | According to the Kinetic theory of gases the collision between the molecules are assumed to be
  • Perfectly elastic
  • Partly elastic
  • Partly inelastic
  • 50% elastic
  • Perfectly inelastic
Q21 | An isolated system
  • Is a specified regon where transfers of energy and/or mass takes place
  • Is a region of constant mass and only energy is allowed to cross the boundaries
  • Cannot transfer either energy or mass to or from the surroundings
  • Is one in which mass within the system is not necessarily constant
  • None of the above
Q22 | If during a process, the entropy of the isolated system increases, the process is
  • Adiabatic
  • Irreversible
  • Reversible
  • Ideal
  • Isothermal
Q23 | A constant volume gas thermometer closely follows
  • Boyle's law
  • Charle's law
  • Gay Lussac's law
  • None of the above
  • Pulsejet
Q24 | In a thermal power plant thermodynamic cycle used is
  • Joule
  • Brayton
  • Carnot
  • Erricson
  • Rankine
Q25 | According to Boyle's law PV = C when the temperature is constant. In this relation the magnitude of C depends upon
  • Pulsejet
  • atmospheric pressure
  • atomicity of the gas
  • quantity of the gas involved
  • molecular weight of the gas