Home
Current Affairs January 2024

What is the correct answer?

4

In case of steady flow compression polytropic process (PVn = constant), the work done on air is the lowest, when

A. n = y = 1.4

B. n = 0

C. n = 1

D. n = 1.66

Correct Answer :

C. n = 1


Related Questions

What is the correct answer?

4

Entropy of the system decreases, when

A. Snow melts into water

B. A gas expands spontaneously from high pressure to low pressure

C. Water is converted into ice

D. Both (B) & (C)

What is the correct answer?

4

Joule-Thomson co-efficient is defined as

A. μ = (∂P/∂T)H

B. μ = (∂T/∂P)H

C. μ = (∂E/∂T)H

D. μ = (∂E/∂P)H

What is the correct answer?

4

A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system

A. its internal energy (U) decreases and its entropy (S) increases

B. U and S both decreases

C. U decreases but S is constant

D. U is constant but S decreases

What is the correct answer?

4

Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ____with the increase of reduced temperature.

A. Decreases

B. Increases

C. Remains constant

D. Decreases logarithmically

What is the correct answer?

4

The activity of an ideal gas is numerically __________ its pressure.

A. More than

B. Less than

C. Equal to

D. Data insufficient, can't be predicted

What is the correct answer?

4

Out of the following refrigeration cycles, which one has the minimum COP (Co-efficient of performance)?

A. Air cycle

B. Carnot cycle

C. Ordinary vapour compression cycle

D. Vapour compression with a reversible expansion engine

What is the correct answer?

4

The number of degrees of freedom at the triple point of water is

A. 0

B. 1

C. 2

D. 3

What is the correct answer?

4

Entropy change of mixing two liquid substances depends upon the

A. Molar concentration

B. Quantity (i.e. number of moles)

C. Both (A) and (B)

D. Neither (A) nor (B)

What is the correct answer?

4

4 kg moles of an ideal gas expands in vacuum spontaneously. The work done is

A. 4 J

B.

C. 0

D. 8 J

What is the correct answer?

4

The main feature of Carnot refrigeration cycle is that, it

A. Does not need the addition of external work for its functioning

B. Transfers heat from high temperature to low temperature

C. Accomplishes the reverse effect of the heat engine

D. None of these

What is the correct answer?

4

y = specific heat ratio of an ideal gas is equal to

A. Cp/Cv

B. Cp/(CP-R)

C. 1 + (R/CV)

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

What is the correct answer?

4

For a constant volume process

A. dE = CpdT

B. dE = CvdT

C. dQ = dE + pdV

D. dW = pdV

What is the correct answer?

4

A refrigeration cycle is the same as a __________ cycle,

A. Turbine

B. Heat engine

C. Reversed heat engine

D. None of these

What is the correct answer?

4

Pick out the wrong statement.

A. A refrigeration cycle violates the second law of thermodynamics

B. Refrigeration cycle is normally represented by a temperature vs. entropy plot

C. In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases

D. One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

What is the correct answer?

4

Forward reaction will be favoured for the exothermic reaction, represented by CO + H2O CO2 + H2, by

A. Low temperature and high pressure

B. Low temperature and low pressure

C. High temperature and high pressure

D. High temperature and low pressure

What is the correct answer?

4

In an ideal solution, the activity of a component equals its

A. Mole fraction

B. Fugacity at the same temperature and pressure

C. Partial pressure

D. None of these

What is the correct answer?

4

Entropy change for an irreversible process taking system and surrounding together is

A. 0

B. > 0

C. < 0

D. None of these

What is the correct answer?

4

The expression, ΔG = nRT. ln(P2/P1), gives the free energy change

A. With pressure changes at constant temperature

B. Under reversible isothermal volume change

C. During heating of an ideal gas

D. During cooling of an ideal gas

What is the correct answer?

4

Which of the following is not a reversible process?

A. Expansion of an ideal gas against constant pressure

B. Atmospheric pressure vaporisation of water at 100°C

C. Solution of NaCl in water at 50°C

D. None of these

What is the correct answer?

4

Entropy change for an irreversible isolated system is

A.

B. 0

C. < 0

D. > 0

What is the correct answer?

4

The expression, nCv(T2 - T1), is for the __________ of an ideal gas.

A. Work done under adiabatic condition

B. Co-efficient of thermal expansion

C. Compressibility

D. None of these

What is the correct answer?

4

Equation which relates pressure, volume and temperature of a gas is called the

A. Equation of state

B. Gibbs Duhem equation

C. Ideal gas equation

D. None of these

What is the correct answer?

4

__________ explains the equilibrium constant for any chemical reaction.

A. Henry's law

B. Law of mass action

C. Hess's law

D. None of these

What is the correct answer?

4

When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is

A. More in vapour phase

B. More in liquid phase

C. Same in both the phases

D. Replaced by chemical potential which is more in vapour phase

What is the correct answer?

4

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.

A. Kinematic viscosity

B. Work

C. Temperature

D. None of these

What is the correct answer?

4

What is the value of ln y (where y = activity co-efficient) for ideal gases?

A. Zero

B. Unity

C. Infinity

D. Negative

What is the correct answer?

4

Joule-Thomson co-efficient depends on the

A. Pressure

B. Temperature

C. Both (A) & (B)

D. Neither (A) nor (B)

What is the correct answer?

4

The minimum number of phases that can exist in a system is

A. 0

B. 1

C. 2

D. 3

What is the correct answer?

4

The extensive properties are

A. Volume, mass and number of moles

B. Free energy, entropy and enthalpy

C. Both (A) and (B)

D. None of these

What is the correct answer?

4

The equation relating E, P, V and T which is true for all substances under all conditions is given by (∂E/∂V)T = T(∂P/∂T)H - P. This equation is called the

A. Maxwell's equation

B. Thermodynamic equation of state

C. Equation of state

D. Redlich-Kwong equation of state