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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on Thermodynamics Set 13
Q1 | The efficiency of an ideal (Carnot engine) depends on
- On the temperature of both the source and the sink
- On the temperature of the source only
- On the temperature of the sink only
- On the construction of engine
- Working substance
Q2 | A choke is applied in a car
- For reduction of speed
- For increasing speed
- For starting in hot weather
- For fuel economy
- For starting in cold weather
Q3 | In a reversible polytropic process
- Some heat transfer occurs
- Entropy remains constant
- Enthalpy remains constant
- Internal energy remains constant
- None of the above
Q4 | Rankine cycle efficiency for a power plant is 29.6%. The Carnot cycle efficiency will be
- Equal to Rankine cycle efficiency
- More than Rankine cycle efficiency
- Less than Rankine cycle efficiency
- There is no comparison for the two
- None of the above
Q5 | The heat flows through solids only by
- Radiation
- Conduction
- microns
- Convection
Q6 | Sadi Carnot was a
- French engineer
- Russian engineer
- Pulsejet
- British engineer
- German engineer
Q7 | Cut of ratio in a steam engine is the ratio of
- Work done by piston after cut off to total work done per cylinder
- Fraction of piston stroke which the piston has travelled when cut off occurs
- Pressure at cut off to supply pressure
- Pressure at cut off to exhaust pressure
- Pressure at cut off to mean effective pressure
Q8 | Which of the following statement about Vanc der Waal's equation is valid?
- Pulsejet
- It represents a straight line on pv versus v plot
- The equation is valid for diatomic gases only
- It is valid for all pressures and temperatures
- It has three roots of identical value at the critical point
Q9 | The statement that the volume of a mixture of ideal gases is equal to the span of the partial volumes which the constituent gases would occupy if each existed alone at the pressure and temperature of the mixture, is known as
- Clapeyrons law
- Maxwell's law
- Leduc's law
- Daltons law
- Clausius law
Q10 | Two vessels of volume 5 litres and 3 litres contain air at a pressure of 3 atmospheres and 5 atmospheres respectively. When the two vessels are connected together by a small tube (at constant temperature) the reusltant pressure will be
- 4.0 atm
- 5.0 atm
- 4.5 atm
- 3.75 atm
- Pulsejet
Q11 | The rate of radiant energy, which is emitted by a surface at any temperature and in small wavelengths is found from the known rate of energy, which under the same conditions would be emitted from a black surface, by multiplying with the absorptivity. Above enunciation is known as
- Planck's law
- Kirchhoff's law
- Stefan Bolzmann's law
- Lambart's rule
- None of the above
Q12 | A gs which satisfies the Kinetic theory of gases is known as
- Manoatomic gas
- Diatomic gas
- Real gas
- Perfect gas
- None of the above
Q13 | Which of the following gas will satisfy, Boyle's law over a wider range of temperatures and pressures?
- Helium
- Pulsejet
- Oxygen
- Hydrogen
- Carbon monoxide
Q14 | The term "pre-whirl" is associated with
- Gas turbines
- Super-charged diesel engines
- Sliding vane type air compressors
- Reciprocating air compressors
- Centrifugal air compressors
Q15 | If a heat engine gives an output of 3 kW and input is 10,000 J/s the thermal efficiency of the engine will be
- 70%
- 30%
- 33.30%
- 66.60%
- 100%
Q16 | An amount of heat given to a gas under isothermal conditions will be
- For a temperature rise
- For doing external work
- For doing external work and also for a temperature rise
- For increasing the internal energy of the gas
- None of the above
Q17 | Two gases X and Y having the same temperature T, the same pressure P and the same volume V are mixed. If the mxiture has the volume V and temperature T, then the pressure of the mixture must be
- 4P
- P
- Pulsejet
- 2P
Q18 | By applying chike in an automobile we get
- Stoichiometric mixture
- Chemically correct mixture
- Weak mixture
- Lean mixture
- Rich mixture
Q19 | The critical temperature of carbondioside is 31.1?C. If the room temperature is 34.7?C, then carbondioxide at room temperature is
- vapour
- wet vapour
- Pulsejet
- superheated vapour
- gas
Q20 | In case of a four cylinder diesel engine, the heat carried away by exhaust gases will be
- 10 to 20 percent
- 50 to 70 percent
- 25 to 35 percent
- 5 to 7 percent
- 7 to 10 percent
Q21 | The ratio of enthalpy rise in rotor of a centrifugal compressor to the enthalpy rise in stage is called
- Adiabatic efficiency
- Degree of reaction
- Volumetric efficiency
- Dynamic pressure ratio
- Static pressure ratio
Q22 | During isothermal process
- Pulsejet
- supply of heat is accompanied by rise in temperature
- rise in entropy is accompanied by rise in temperature
- drop in pressure is accompanied by drop in volume
- rejection of heat is accompanied by decrease in volume
Q23 | Which of the following relations is not applicable to free expansion process?
- Heat supplied = Zero
- Change in internal energy = Zero
- Change in temperature = Zero
- Heat rejected = Zero
- Work done = Zero
Q24 | Maxwell's thermodynamic relations are valid for
- Transient conditions only
- Closed system only
- Only reversible processes
- All processes
- A thermodynamic system in equilibrium
Q25 | If during a process, the entropy of the isolated system increases, the process is
- Adiabatic
- Ideal
- Isothermal
- Reversible
- Irreversible