The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (when, T1 > T2) is given by (T1 - T2)/T1. The co-efficient of performance (C.O.P.) of a Carnot heat pump operating between T1 and T2 is given by
T1/(T1-T2)
T2/(T1-T2)
T1/T2
T2/R1
Correct Answer :
A. T1/(T1-T2)
Related Questions
The partial pressure of each constituent present in an alloy is __________ the total vapor pressure exerted by the alloy.
Less than
Equal to
More than
Either (B) or (C); depends on the type of alloy
What is the value of Joule-Thomson co-efficient for an ideal gas?
+ve
-ve
0
∞
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
At constant temperature and pressure, for one mole of a pure substance, the ratio of the free energy to the chemical potential is
Zero
One
Infinity
Negative
Maxwell's relation corresponding to the identity, dH = dS = Vdp + Σμi dni is
(∂T/∂V)S, ni = -(∂P/∂S)V, ni
(∂S/∂P)T, ni = (∂V/∂T)P, ni
(∂S/∂V)T, ni = (∂P/∂T)V, ni
(∂T/∂P)S, ni = (∂V/∂S)P, ni
A system is said to be isopiestic, if there is no __________ change.
Temperature
Pressure
Volume
None of these
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
Filling of gas from a high pressure cylinder into small bottles is an example of a/an __________ process.
Equilibrium
Adiabatic
Steady
Unsteady
Heat requirement for decomposition of a compound into its elements is __________ that is evolved during the formation of that compound from its elements.
The same
Less than
Greater than
Different than
PVγ = Constant (where, γ = Cp/Cv) is valid for a/an __________ process.
Isothermal
Isentropic
Isobaric
Adiabatic
In jet refrigerators, the refrigerating fluid is practically always
Water
Ammonia
Freon
Brine
For a constant volume process
dE = CpdT
dE = CvdT
dQ = dE + pdV
dW = pdV
A/an __________ system is exemplified by a vessel containing a volatile liquid in contact with its vapor.
Isolated
Closed
Open
None of these
For an isothermal reversible compression of an ideal gas
Only ΔE = 0
Only ΔH =0
ΔE = ΔH = 0
dQ = dE
Entropy is a/an
State function
Macroscopic property
Extensive property
None of these
For an isothermal process, the internal energy of a gas
Increases
Decreases
Remains unchanged
Data insufficient, can't be predicted
Compressibility factor for almost all the gases are approximately same at the same
Pressure and temperature
Reduced pressure and reduced temperature
Critical pressure and critical temperature
None of these
The absolute entropy for all crystalline substances at absolute zero temperature is
Zero
Negative
More than zero
Indeterminate
Heating of water under atmospheric pressure is an __________ process.
Isochoric
Isobaric
Adiabatic
Isothermal
As pressure approaches zero, the ratio of fugacity to pressure (f/P) for a gas approaches
Zero
Unity
Infinity
An indeterminate value
For a single component two phase mixture, the number of independent variable properties are
Two
One
Zero
Three
When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is
More in vapour phase
More in liquid phase
Same in both the phases
Replaced by chemical potential which is more in vapour phase
What is the value of ln y (where y = activity co-efficient) for ideal gases?
Zero
Unity
Infinity
Negative
A cylinder contains 640 gm of liquid oxygen. The volume occupied (in litres) by the oxygen, when it is released and brought to standard conditions (0°C, 760 mm Hg) will be __________ litres.
448
224
22.4
Data insufficient; can't be computed
The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.
Kinematic viscosity
Work
Temperature
None of these
Which of the following is an extensive property of a system?
Heat capacity
Molal heat capacity
Pressure
Concentration
Entropy change of the reaction, H2O (liquid) → H2O (gas), is termed as the enthalpy of
Solution
Vaporisation
Formation
Sublimation
A gas has a volume of 27.3 c.c. at 0°C. Its volume at 10°C (if pressure remains unchanged) will be __________ c.c.
2.73
28.3
273
283
At the critical point of a substance
The surface tension vanishes
Liquid and vapour have the same density
There is no distinction between liquid and vapour phases
All (A), (B) and (C)
The equation DU = Tds - PdV is applicable to infinitesimal changes occuring in
An open system of constant composition
A closed system of constant composition
An open system with changes in composition
A closed system with changes in composition