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4

Entropy of a substance remains constant during a/an __________ change.

A. Reversible isothermal

B. Irreversible isothermal

C. Reversible adiabatic

D. None of these

Correct Answer :

C. Reversible adiabatic


Related Questions

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4

Pick out the undesirable property for a good refrigerant.

A. High thermal conductivity

B. Low freezing point

C. Large latent heat of vaporisation

D. High viscosity

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4

A/an __________ system is exemplified by a vessel containing a volatile liquid in contact with its vapor.

A. Isolated

B. Closed

C. Open

D. None of these

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For a spontaneous process, free energy

A. Is zero

B. Increases

C. Decreases whereas the entropy increases

D. And entropy both decrease

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4

The enthalpy change when ammonia gas is dissolved in water is called the heat of

A. Solution

B. Formation

C. Dilution

D. Combustion

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During Joule-Thomson expansion of gases

A. Enthalpy remains constant

B. Entropy remains constant

C. Temperature remains constant

D. None of these

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For spontaneous changes in an isolated system (S = entropy)

A. ds = 0

B. ds <0

C. ds > 0

D. ds = Constant

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4

Claude's liquefaction process employs the cooling of gases by

A. Expansion in an engine

B. Following a constant pressure cycle

C. Throttling

D. None of these

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4

__________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low.

A. Bucket

B. Throttling

C. Separating

D. A combination of separating & throttling

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4

The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and noctane into pure compounds each at 1 atm is

A. -2 RT ln 0.5

B. -RT ln 0.5

C. 0.5 RT

D. 2 RT

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4

Which of the following liquid metals has the highest thermal conductivity?

A. Molten sodium

B. Molten lead

C. Mercury

D. Molten potassium

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4

In reactions involving solids and liquids (where change in volume is negligible), the heat of reaction at constant pressure as compared to that at constant volume is

A. More

B. Less

C. Same

D. Unpredictable; depends on the particular reaction

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4

At triple point (for one component system), vapour pressure of solid as compared to that of liquid will be

A. More

B. Less

C. Same

D. More or less; depending on the system

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4

In a working refrigerator, the value of COP is always

A. 0

B. < 0

C. < 1

D. > 1

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All gases except __________ shows a cooling effect during throttling process at atmospheric temperature and pressure.

A. Oxygen

B. Nitrogen

C. Air

D. Hydrogen

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A gas performs the maximum work, when it expands

A. Non-uniformly

B. Adiabatically

C. Isobarically

D. Isothermally

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Equilibrium constant of a reaction varies with the

A. Initial concentration of the reactant

B. Pressure

C. Temperature

D. None of these

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4

Pick out the wrong statement.

A. The values of (∂P/∂V)T and (∂2P/∂V2)T are zero for a real gas at its critical point

B. Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process

C. Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures

D. During a reversible adiabatic process, the entropy of a substance remains constant

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In case of an __________ process, the temperature of the system increases.

A. Isothermal compression

B. Isothermal expansion

C. Adiabatic expansion

D. Adiabatic compression

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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

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4

In an irreversible process

A. Tds = dE - dW = 0

B. dE - dW - Tds = 0

C. Tds - dE + dW < 0

D. Tds - dT + dW < 0

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An isolated system can exchange __________ with its surroundings.

A. Matter

B. Energy

C. Neither matter nor energy

D. Both matter and energy

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4

Gibbs-Helmholtz equation is

A. ΔF = ΔH + T [∂(ΔF)/∂T]P

B. ΔF = ΔH - TΔT

C. d(E - TS) T, V < 0

D. dP/dT = ΔHvap/T.ΔVvap

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Degrees of freedom at triple point will be

A. 0

B. 1

C. 2

D. 3

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A system is said to be at equilibrium, if the entropy of the system has reached __________ value.

A. Minimum

B. Zero

C. Maximum

D. None of these

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4

Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is

A. Positive

B. Negative

C. Zero

D. Infinity

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(1/V) (∂V/∂T)P is the mathematical expression

A. Joule-Thomson co-efficient

B. Specific heat at constant pressure (Cp)

C. co-efficient of thermal expansion

D. Specific heat at constant volume (CV)

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In a reversible process

A. Tds = dE + dW

B. dE - dW = Tds

C. dW - dE = Tds

D. Tds - dW + dE >0

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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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The ratio of equilibrium constants (Kp2/Kp1) at two different temperatures is given by

A. (R/ΔH) (1/T1 - 1/T2)

B. (ΔH/R) (1/T1 - 1/T2)

C. (ΔH/R) (1/T2 - 1/T1)

D. (1/R) (1/T1 - 1/T2)

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Rotary lime kiln is an example of a/an __________ system.

A. Closed

B. Open

C. Isolated

D. Non-thermodynamic