Which of the following has the least thermal efficiency?
Steam engine
Carnot engine
Diesel engine
Otto engine
Correct Answer :
A. Steam engine
Related Questions
With increase in compression ratio, the efficiency of the otto engine
Increases
Decreases
Remain constant
Increases linearly
During the phase transition, __________ changes.
Pressure
Volume
Temperature
All (A), (B) and (C)
Gibbs free energy of mixing at constant pressure and temperature is always
0
∞
+ ve
- ve
A change in state involving a decrease in entropy can be spontaneous, only if
It is exothermic
It is isenthalpic
It takes place isothermally
It takes place at constant volume
Consider the process A & B shown in the figure given below: In this case, it is possible that
Both the processes are adiabatic
Both the processes are isothermal
Process A is isothermal while B is adiabatic
Process A is adiabatic while B is isothermal
For a constant pressure reversible process, the enthalpy change (ΔH) of the system is
Cv.dT
Cp.dT
∫ Cp.dT
∫ Cv.dT
High __________ is an undesirable property for a good refrigerant.
Specific heat
Latent heat of vaporisation
Viscosity
Specific vapor volume
Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is
1
2
3
4
In the equation, PVn = constant, if the value of n is in between 1 and y (i.e. Cp/Cv), then it represents a reversible __________ process.
Isometric
Polytropic
Isentropic
Isobaric
For the gaseous phase chemical reaction, C2H4(g) + H2O(g) ↔ C2H5OH(g), the equilibrium conversion does not depend on the
Steam to ethylene ratio
Temperature
Pressure
None of these
Reduced pressure of a gas is the ratio of its
Pressure to critical pressure
Critical pressure to pressure
Pressure to pseudocritical pressure
Pseudocritical pressure to pressure
Gibbs-Duhem equation
States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure
Applies only to binary systems
Finds no application in gas-liquid equilibria involved in distillation
None of these
When dilute aqueous solutions of two salts are mixed, the process is associated with
Decrease in temperature
Increase in temperature
No change in temperature
Change in temperature which is a function of composition
In the equation, PVn = Constant, if the value of n = 0, then it represents a reversible __________ process.
Isobaric
Isothermal
Isentropic
Isometric
The variation of heat of reaction with temperature at constant pressure is given by the __________ law.
Kelvin's
Antoines
Kirchoffs
None of these
Near their critical temperatures, all gases occupy volumes __________ that of the ideal gas.
Less than
Same as
More than
Half
Critical compressibility factor for all substances
Are more or less constant (vary from 0.2 to 0.3)
Vary as square of the absolute temperature
Vary as square of the absolute pressure
None of these
Work done in case of free expansion is
Indeterminate
Zero
Negative
None of these
The fugacity of a gas in a mixture is equal to the product of its mole fraction and its fugacity in the pure state at the total pressure of the mixture. This is
The statement as per Gibbs-Helmholtz
Called Lewis-Randall rule
Henry's law
None of these
For spontaneous changes in an isolated system (S = entropy)
ds = 0
ds <0
ds > 0
ds = Constant
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
Degree of freedom of a system consisting of a gaseous mixture of H2 and NH3 will be
0
1
2
3
Domestic refrigerator usually works on the __________ refrigeration cycle.
Carnot
Air
Absorption
vapour-ejection
For a reversible process involving only pressure-volume work
(dF)T, p < 0
(dF)T, p > 0
(dF)T, p = 0
(dA)T, v < 0
Any substance above its critical temperature exists as
Saturated vapour
Solid
Gas
Liquid
To obtain integrated form of Clausius-Clapeyron equation, ln (P2/P1) = (ΔHV/R) (1/T1 - 1/T2) from the exact Clapeyron equation, it is assumed that the
Volume of the liquid phase is negligible compared to that of vapour phase
Vapour phase behaves as an ideal gas
Heat of vaporisation is independent of temperature
All (A), (B) & (C)
A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to the __________ mean of P1 and P2. (where, P1 and P2 are initial and final pressures respectively)
Logarithmic
Arithmetic
Geometric
Harmonic
Generation of heat by friction is an example of a/an __________ change.
Isothermal
Irreversible
Adiabatic
Reversible
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
An isentropic process is carried out at constant
Volume
Pressure
Temperature
All (A), (B) and (C)