A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect?
Vapor compression cycle using expansion valve
Air refrigeration cycle
Vapor compression cycle using expansion engine
Carnot refrigeration cycle
Correct Answer :
D. Carnot refrigeration cycle
Related Questions
A/an __________ system is exemplified by a vessel containing a volatile liquid in contact with its vapor.
Isolated
Closed
Open
None of these
__________ does not change during phase transformation processes like sublimation, melting & vaporisation.
Entropy
Gibbs free energy
Internal energy
All (A), (B) & (C)
Joule-Thomson effect i.e., a throttling process is a constant __________ process.
Entropy
Temperature
Internal energy
Enthalpy
PVy = constant, holds good for an isentropic process, which is
Reversible and isothermal
Isothermal and irreversible
Reversible and adiabatic
Adiabatic and irreversible
Pick out the wrong statement.
An ideal liquid or solid solution is defined as one in which each component obeys Raoult's law
If Raoult's law is applied to one component of a binary mixture; Henry's law or Raoult's law is applied to the other component also
Henry's law is rigorously correct in the limit of infinite dilution
None of these
Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the
Calorific value
Heat of reaction
Heat of combustion
Heat of formation
The activity of an ideal gas is numerically __________ its pressure.
More than
Less than
Equal to
Data insufficient, can't be predicted
A gas shows deviation from ideal behaviour at
Low pressure and high temperature
Low pressure and low temperature
Low temperature and high pressure
High temperature and high pressure
The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition.
Internal energy
Enthalpy
Gibbs free energy
Helmholtz free energy
Which of the following is not an equation of state?
Bertholet equation
Clausius-Clapeyron equation
Beattie-Bridgeman equation
None of these
For a constant volume process __________ by the system is used only to increase the internal energy.
Heat absorbed
Work done
Both (A) & (B)
Neither (A) nor (B)
Pick out the wrong statement.
The net change in entropy in any reversible cycle is always zero
The entropy of the system as a whole in an irreversible process increases
The entropy of the universe tends to a maximum
The entropy of a substance does not remain constant during a reversible adiabatic change
Henry's law is closely obeyed by a gas, when its __________ is extremely high.
Pressure
Solubility
Temperature
None of these
Absorption/evolution of heat during conversion of a substance from one allotropic form to another is termed as the heat of
Sublimation
Fusion
Transition
Vaporisation
A gas can be liquefied by pressure alone only, when its temperature is __________ its critical temperature.
Less than
More than
Equal to or higher than
Less than or equal to
Pick out the wrong statement.
Trouton's ratio of non-polar liquids is calculated using Kistyakowsky equation
Thermal efficiency of a Carnot engine is always less than 1
An equation relating pressure, volume and temperature of a gas is called ideal gas equation
None of these
On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)s and the slope of the reversible isothermal line (∂P/ ∂V)T are related as (where, y = Cp/Cv)
(∂P/∂V)S = (∂P/∂V)T
(∂P/∂V)S = [(∂P/∂V)T]Y
(∂P/∂V)S = y(∂P/∂V)T
(∂P/∂V)S = 1/y(∂P/∂V)T
__________ explains the equilibrium constant for any chemical reaction.
Henry's law
Law of mass action
Hess's law
None of these
Third law of thermodynamics is concerned with the
Value of absolute entropy
Energy transfer
Direction of energy transfer
None of these
Which of the following is not an intensive property?
Volume
Density
Temperature
Pressure
A domestic refrigerator has a/an __________ cooled condenser.
Water
Air
Evaporative
Gas
In jet refrigerators, the refrigerating fluid is practically always
Water
Ammonia
Freon
Brine
Internal energy is equal to the heat absorbed in case of a/an __________ process.
Constant volume
Polytropic
Adiabatic
Constant pressure
A gas mixture of three components is brought in contact with a dispersion of an organic phase in water. The degree of freedom of the system is
3
4
5
6
Which of the following is Clausius-Clapeyron Equation for vaporisation of an ideal gas under the condition that the molar volume of liquid is negligible compared to that of the vapor?
d ln p/dt = Hvap/RT2
d ln p/dt = RT2/Hvap
dp/dt = RT2/Hvap
dp/dt = Hvap/RT2
__________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low.
Bucket
Throttling
Separating
A combination of separating & throttling
At __________ point, all the three phases (i.e. solid, liquid and gas) co-exist.
Eutectic
Triple
Plait
Critical
Heat is added at constant temperature in an ideal __________ cycle.
Stirling
Brayton
Rankine
None of these
For a spontaneous process, free energy
Is zero
Increases
Decreases whereas the entropy increases
And entropy both decrease
Air enters an adiabatic compressor at 300K. The exit temperature for a compression ratio of 3, assuming air to be an ideal gas (Y = Cp/Cv = 7/5) and the process to be reversible, is
300 × (32/7)
300 × (33/5)
300 × (333/7)
300 × (35/7)