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4

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

A. T1/(T1-T2)

B. T2/(T1-T2)

C. T1/T2

D. T2/R1

Correct Answer :

A. T1/(T1-T2)


Related Questions

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4

The internal energy of an ideal gas does not change in a reversible __________ process.

A. Isothermal

B. Adiabatic

C. Isobaric

D. Isometric

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4

The adiabatic throttling process of a perfect gas is one of constant enthalpy

A. In which there is a temperature drop

B. Which is exemplified by a non-steady flow expansion

C. Which can be performed in a pipe with a constriction

D. In which there is an increase in temperature

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4

Which of the following is not a unit of the equilibrium constant Kp? (where, Δx = number of moles of products number of moles of reactants)

A. (atm)Δx, when Δx is negative

B. (atm)Δx, when Δx is positive

C. Dimensionless, when Δx = 0

D. (atm)Δx2, when Δx > 0

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4

If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the

A. Maxwell's equation

B. Clausius-Clapeyron Equation

C. Van Laar equation

D. Nernst Heat Theorem

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4

Joule-Thomson Co-efficient at any point on the inversion curve is

A.

B. +ve

C. 0

D. -ve

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4

The Joule-Thomson co-efficient is defined as (∂T/∂P)H. Its value at the inversion point is

A.

B. 1

C. 0

D. -ve

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4

The second law of thermodynamics states that

A. The energy change of a system undergoing any reversible process is zero

B. It is not possible to transfer heat from a lower temperature to a higher temperature

C. The total energy of system and surrounding remains the same

D. None of the above

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4

Which of the following is an extensive property of a system?

A. Heat capacity

B. Molal heat capacity

C. Pressure

D. Concentration

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4

Work done may be calculated by the expression ∫ p dA for __________ processes.

A. Non-flow reversible

B. Adiabatic

C. Both (A) and (B)

D. Neither (A) nor (B)

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4

Which of the following has the least thermal efficiency?

A. Steam engine

B. Carnot engine

C. Diesel engine

D. Otto engine

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4

Compressibility factor of a gas is

A. Not a function of its pressure

B. Not a function of its nature

C. Not a function of its temperature

D. Unity, if it follows PV = nRT

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4

The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is

A. Less pronounced

B. More pronounced

C. Equal

D. Data insufficient, can't be predicted

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4

What is the ratio of adiabatic compressibility to isothermal compressibility?

A. 1

B. < 1

C. > 1

D. >> 1

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4

Boiling of liquid is accompanied with increase in the

A. Vapor pressure

B. Specific Gibbs free energy

C. Specific entropy

D. All (A), (B) and (C)

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4

Heat pump

A. Accomplishes only space heating in winter

B. Accomplishes only space cooling in summer

C. Accomplishes both (A) and (B)

D. Works on Carnot cycle

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4

The following heat engine produces power of 100,000 kW. The heat engine operates between 800 K and 300 K. It has a thermal efficiency equal to 50% of that of the Carnot engine for the same temperature. The rate at which heat is absorbed from the hot reservoir is

A. 100,000 kW

B. 160,000 kW

C. 200,000 kW

D. 320,000 kW

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4

Solid and liquid phases of a substance are in equilibrium at the

A. Critical temperature

B. Melting point

C. Freezing point

D. Both (B) and (C)

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4

In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in

A. Enhanced COP

B. Decreased COP

C. No change in the value of COP

D. Increased or decreased COP; depending upon the type of refrigerant

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4

PVy = constant, holds good for an isentropic process, which is

A. Reversible and isothermal

B. Isothermal and irreversible

C. Reversible and adiabatic

D. Adiabatic and irreversible

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4

Pick out the wrong statement.

A. Enthalpies of all elements in their standard states are assumed to be zero

B. Combustion reactions are never endothermic in nature

C. Heat of reaction at constant volume is equal to the change in internal energy

D. Clausius-Clapeyron equation is not applicable to melting process

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4

Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation.

A. Gibbs-Duhem

B. Maxwell's

C. Clapeyron

D. None of these

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4

Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.).

A. Entropy

B. Internal energy

C. Enthalpy

D. Gibbs free energy

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4

A gas performs the maximum work, when it expands

A. Non-uniformly

B. Adiabatically

C. Isobarically

D. Isothermally

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4

For an ideal gas, the chemical potential is given by

A. RT d ln P

B. R d ln P

C. R d ln f

D. None of these

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4

Pick out the wrong statement.

A. The chemical potential of a pure substance depends upon the temperature and pressure

B. The chemical potential of a component in a system is directly proportional to the escaping tendency of that component

C. The chemical potential of ith species (μi) in an ideal gas mixture approaches zero as the pressure or mole fraction (xi) tends to be zero at constant temperature

D. The chemical potential of species 'i' in the mixture (μi) is mathematically represented as,μi = ∂(nG)/∂ni]T,P,nj where, n, ni and nj respectively denote the total number of moles, moles of ith species and all mole numbers except ith species. 'G' is Gibbs molar free energy

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4

Pick out the wrong statement.

A. A closed system does not permit exchange of mass with its surroundings but may permit exchange of energy.

B. An open system permits exchange of both mass and energy with its surroundings

C. The term microstate is used to characterise an individual, whereas macro-state is used to designate a group of micro-states with common characteristics

D. None of the above

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4

The equation, Cp - Cv = R, is true for __________ gas.

A. No

B. Any real

C. Only ideal

D. Both (B) and (C)

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4

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.

A. 2.73

B. 28.3

C. 273

D. 283

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4

In an ideal gas mixture, fugacity of a species is equal to its

A. Vapor pressure

B. Partial pressure

C. Chemical potential

D. None of these

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4

The molar excess Gibbs free energy, gE, for a binary liquid mixture at T and P is given by, (gE/RT) = A . x1. x2, where A is a constant. The corresponding equation for ln y1, where y1 is the activity co-efficient of component 1, is

A. A . x22

B. Ax1

C. Ax2

D. Ax12