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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on Thermodynamics Set 9
Q1 | The general gas equation is
- PVn = constant
- PV = (RT)m
- PV = constant
- PV = mRT
- PV = RT
Q2 | Heat is transferred from an insulated steam pipe to the surrounding still air by
- Conduction
- Radiation
- All the above together
- Forced convection
- Free convection
Q3 | Three Carnot engines A, B and C having source temperature of 750?K, 700?K and 650?K have sink temperatures respectively 400?k, 350?k and 300?k. Which engine is the least efficient?
- All being Carnot engine have identical efficiencies
- Pulsejet
- Engine B
- Engine C
- Engine A
Q4 | The energy required to heat 1 gm of water from 0?F to 0?C will be nearly
- 32 cal
- 74.6 J
- Pulsejet
- zero
- 32 J
Q5 | For a gas the difference between the values of Cp and Cv aceounts for
- external work done
- increased kinetic energy of molecules
- increase in volume is more rapid as compared to that of pressure
- None of the above
- Pulsejet
Q6 | The critical pressure at which latent heat of vaporisation for water is zero is
- 250.6 kg/cm2
- 100 kg/cm2
- 228.6 kg/cm2
- 235.6 kg/cm2
- 215.1 kg/cm2
Q7 | Brayton cycles processes are
- Two isothermals constant volume a constant pressure
- One constant pressure, one constant volume, two adiabatics
- Two isentropics and two constant pressure
- Two isothermals and two isentropics
- Two isentropics and two constant volume
Q8 | A gas which obeys kinetic theory perfectly is known as
- Diatomic gas
- Monoatomic gas
- Perfect gas
- Pure gas
- Real gas
Q9 | In an automobile the gear box is fitted between
- Differential and wheels
- Engine and clutch
- Engine and flywheels
- Clutch and wheels
- Clutch and differential
Q10 | In an isothermal process
- Pressure remains constant
- Inter-molecular energy remain constant
- Temperature remains constant
- Kinetic energy remains constant
- Volume remains constant
Q11 | Which of the following gas has the highest values for the adiabatic index?
- Air
- Helium
- Methane
- Oxygen
- Nitrogen
Q12 | The mixing process of two fluids is always considered as
- reversible or irreversible depending upon the gases involved
- Pulsejet
- reversible
- irreversible
Q13 | In which of the following energy conversion takes place at ambient temperature?
- Solar radiation
- Pulsejet
- Thermionic generator
- Magnetohydrodynamic conversion
- Battery producing electrical energy
Q14 | If the sun becomes twice as hot
- its output of radiation energy will fall
- it will radiate predominantly in infra-red
- it will disintegrate into fragments
- Pulsejet
- it will radiate predominantly ultraviolet
Q15 | On a temperature-entropy diagram the slope of constant pressure line is given by
- S/T
- Cv/T
- T/Cp
- T/Cv
- T/S
Q16 | Planck's law of radiation is applicable to
- Radiation of any kind
- Temperature radiation
- Monochromatic radiation
- Thermal radiation
- None of the above
Q17 | Identify the correct statement
- Thermal conductivity is independent of temperature
- Thermal conductivity increases with time
- Thermal conductivity varies with temperature
- Thermal conductivity increases with molecular weight
- Thermal conductivity increases as the rate of heat flow increases
Q18 | In a closed system, the change in enthalpy will be equal to the heat transferred when a reversible process takes place at constant
- Pressure
- Volume
- Entropy
- Temperature
- Internal energy
Q19 | The adiabatic horse power required to deliver 4 cu. M per minute of free air from 1 ata and 15?C to a received pressure at 7 ata would be in the range
- 20 ? 25
- 5 ? 7
- 7 ? 10
- 15 ? 20
- 10 ? 15
Q20 | If a closed circuit is made of two dissimilar metals, an electric current flows in the circuit whdn the two junctions are maintained at different temperatures. This phenomenon is known as
- Seeback effect
- Peltier effect
- Maxwell's effect
- Faraday's effect
- Thomson effect
Q21 | Thermal efficiency of most of the internal combustion engines lies in the range
- 50 to 75 percent
- 90 to 100 percent
- 20 to 35 percent
- 75 to 90 percent
- 35 to 50 percent
Q22 | A body of weight 100 N falls freely through a distance of 10 m against an atmospheric drag force of 5 N. Considering the body as the system, the work interaction is
- 250 Nm
- 1050 Nm
- 1000 Nm
- Pulsejet
- 50 Nm
Q23 | One bar pressure is the same as
- 1000 N/m2
- 100 N/m2
- 100,000 N/m2
- 1 N/m2
- 1000,000 N/m2
Q24 | When a gas expands in a closed vessel, the maximum work will be done when the process is at constant
- Pressure
- Enthalpy
- Volume
- Entropy
- Temperature
Q25 | The RMS velocity of hydrogen gas at N.T.P. is nearly
- 4839 m/s
- 839 m/s
- 1839 m/s
- 2839 m/s
- 3839 m/s