Description : What happens in a reversible adiabatic expansion process? (A) Heating takes place (B) Cooling takes place (C) Pressure is constant (D) Temperature is constant
Last Answer : (B) Cooling takes place
Description : The expression, ∆G = 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
Last Answer : (A) With pressure changes at constant temperature
Description : Air enters an adiabatic compressor at 300K. The exit temperature for a compression ratio of 3, assuming air to be an ideal gas (Y = Cp/Cv = 7/5) and the process to be reversible, is (A) 300 × (32/7) (B) 300 × (33/5) (C) 300 × (333/7) (D) 300 × (35/7)
Last Answer : A) 300 × (32/7)
Description : Adiabatic heating and Adiabatic cooling really means _________ and _________ respectively. a. raising the temp and lowering the temp b. maintaining the pressure and changing the temperature c. decreasing the volume and increasing the pressure d. lowering the temp and raising the temp
Last Answer : raising the temp and lowering the temp
Description : Claude process of gas liquefaction employs (A) Merely compression of gas beyond its critical pressure (B) Joule-Thomson expansion cooling (C) Heat exchange with colder stream (D) Adiabatic expansion against a piston or in a turbine
Last Answer : (D) Adiabatic expansion against a piston or in a turbine
Description : Which of the following non-flow reversible compression processes require maximum work? (A) Adiabatic process (B) Isothermal process (C) Isobaric process (D) All require same work
Last Answer : (A) Adiabatic process
Description : Pick out the wrong statement (A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity (B) When water is cooled from 80 to 70°C by exposure ... & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure
Last Answer : (D) Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure
Description : Pick out the wrong statement: (A) The expansion of a gas in vacuum is an irreversible process (B) An isometric process is a constant pressure process (C) Entropy change for a reversible adiabatic process is zero (D) Free energy change for a spontaneous process is negative
Last Answer : (B) An isometric process is a constant pressure process
Description : When the expansion of compression of gas takes place without transfer of heat to or from the gas the process is called a. reversible b. adiabatic c. polytropic d. isothermal
Last Answer : adiabatic
Description : Which of the following processes are thermodynamically reversible (a) throttling (b) free expansion (c) constant volume and constant pressure (d) hyperbolic and pV = C (e) isothermal and adiabatic.
Last Answer : Answer : e
Description : Adiabatic process is (A) Essentially an isentropic process is___________ (B) Non-heat transfer process (C) Reversible process (D) Constant temperature process
Last Answer : (B) Non-heat transfer process
Description : __________ remains constant during the adiabatic cooling of moist air. (A) Wet bulb temperature (B) Dry bulb temperature (C) Relative humidity (D) Specific humidity
Last Answer : Option A
Description : Which of the following is not correct for a reversible adiabatic process? (A) TV γ-1 = constant (B) p 1-γ .T Y = constant (C) PV γ = constant (D) None of these
Last Answer : (D) None of these
Description : In polytropic process (PV n = constant), if n = 1; it means a/an __________ process. (A) Adiabatic (B) Reversible (C) Isothermal (D) None of these
Last Answer : (C) Isothermal
Description : 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
Last Answer : C) Reversible and adiabatic
Description : In the equation, PVn = constant, if the value of n = ± ∞, then it represents a reversible __________ process. (A) Adiabatic (B) Isometric (C) Isentropic (D) Isothermal
Last Answer : (B) Isometric
Description : Entropy of a substance remains constant during a/an __________ change. (A) Reversible isothermal (B) Irreversible isothermal (C) Reversible adiabatic (D) None of these
Last Answer : (C) Reversible adiabatic
Description : In the equation PVn = constant, if the value of n = y = Cp/Cv, then it represents a reversible __________ process. (A) Isothermal (B) Adiabatic (C) Isentropic (D) Polytropic
Last Answer : (C) Isentropic
Description : Pick out the wrong statement. (A) The net change in entropy in any reversible cycle is always zero (B) The entropy of the system as a whole in an irreversible process increases (C) The ... to a maximum (D) The entropy of a substance does not remain constant during a reversible adiabatic change
Last Answer : (D) The entropy of a substance does not remain constant during a reversible adiabatic change
Description : In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process. (A) Isothermal (B) Isobaric (C) Polytropic (D) Adiabatic
Last Answer : (A) Isothermal
Description : The expression for entropy change given by, ΔS = - nR ln (P2/P1), holds good for (A) Expansion of a real gas (B) Reversible isothermal volume change (C) Heating of an ideal gas (D) Cooling of a real gas
Last Answer : (B) Reversible isothermal volume change
Description : The expression for entropy change given by, ΔS = nR ln (V2/V1) + nCvln (T2/T1) is valid for (A) Reversible isothermal volume change (B) Heating of a substance (C) Cooling of a substance (D) Simultaneous heating and expansion of an ideal gas
Last Answer : (D) Simultaneous heating and expansion of an ideal gas
Description : In a single stage reciprocating air compressor, the work done on air to compressor is from suction pressure to delivery pressure will be minimum when the compression is A. Isothermal process B. Adiabatic process C. Polytropic process D. Constant pressure process.
Last Answer : ANSWER : A
Description : Consider the following processes: [IES-1999] 1. Constant pressure heat addition. 2. Adiabatic compression. 3. Adiabatic expansion. 4. Constant pressure heat rejection. The correct sequence of these processes in Rankine cycle is: (a) 1, 2, 3, 4 (b) 2, 1, 4, 3 (c) 2, 1, 3, 4 (d) 1, 2, 4, 3
Last Answer : (c) 2, 1, 3, 4
Description : Adiabatic compression is one in which A. Temperature during compression remains constant B. No heat leaves or enters the compressor cylinder during compression C. Temperature rise follows a linear relationship D. Work done is maximum.
Last Answer : ANSWER : B
Description : A process, in which the temperature of the working substance remains constant during its expansion or compression, is called A. isothermal process B. hyperbolic process C. adiabatic process D. polytropic process
Last Answer : Answer: A
Description : Joule-Thomson co-efficient is the ratio of (A) Pressure change to temperature change occuring during adiabatic compression of a gas (B) Pressure change to temperature change occuring during adiabatic ... a gas (D) Temperature change to pressure change occuring during adiabatic throttling of a gas
Last Answer : (D) Temperature change to pressure change occuring during adiabatic throttling of a gas
Description : The thermodynamic law, PVy = constant, is not applicable in case of (A) Ideal compression of air (B) Free expansion of an ideal gas (C) Adiabatic expansion of steam in a turbine (D) Adiabatic compression of a perfect gas
Last Answer : (B) Free expansion of an ideal gas
Description : The thermodynamic law, PVy = constant, is not followed by the (A) Free expansion of an ideal gas (B) Adiabatic expansion of steam in turbine (C) Adiabatic compression of air (D) Ideal compression of air
Description : Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for ... a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature
Last Answer : (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs
Description : Which of the following processes is followed by unsaturated air (with dry bulb temperature 12°C and relative humidity 47%) passing through water spray washer (temperature of water being constant at 40°C ... (B) Heating only (C) Both heating and humidification (D) Evaporative cooling
Last Answer : (C) Both heating and humidification
Description : Which of the following psychrometric processes is followed by water vapour laden unsaturated air, when it is passed through solid or liquid adsorbent? (A) Cooling and dehumidification ... (C) Dehumidification with dry bulb temperature remaining constant (D) None of these
Last Answer : (B) Heating and dehumidification at almost constant wet bulb temperature
Description : During adiabatic, internally reversible process, what is true about the change in entropy? A. It is temperature-dependent B. It is always greater than zero C. It is always zero D. It is always less than zero
Last Answer : It is always zero
Description : Which one of the following methods can be adopted to obtain isothermal compression in an air compressor? A. Increasing the weight of the compressor B. Inter-stage heating C. Atmospheric cooling D. Providing appropriate dimensions to the cylinder
Description : In case of an __________ process, the temperature of the system increases. (A) Isothermal compression (B) Isothermal expansion (C) Adiabatic expansion (D) Adiabatic compression
Last Answer : (D) Adiabatic compression
Description : Pick out the correct statement. (A) The available energy in an isolated system for all irreversible (real) processes decreases (B) The efficiency of a Carnot engine increases, if the sink temperature is decreased ... condition is the change in Helmholtz free energy (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : When a gas in a vessel expands, its internal energy decreases. The process involved is (A) Reversible (B) Irreversible (C) Isothermal (D) Adiabatic
Last Answer : (A) Reversible
Description : Specific heat of a gas for a reversible adiabatic process is (A) Negative (B) Zero (C) Infinity (D) None of these
Last Answer : (B) Zero
Description : Entropy change in case of reversible adiabatic process is (A) Minimum (B) Zero (C) Maximum (D) Indeterminate
Description : Pick out the correct statement: (A) In an isothermal system, irreversible work is more than reversible work (B) Under reversible conditions, the adiabatic work is less than isothermal work (C) ... state functions' (D) Matter and energy cannot be exchanged with the surroundings in a closed system
Last Answer : (B) Under reversible conditions, the adiabatic work is less than isothermal work
Description : The expression for the work done for a reversible polytropic process can be used to obtain the expression for work done for all processes, except reversible __________ process. (A) Isobaric (B) Isothermal (C) Adiabatic (D) None of these
Last Answer : (B) Isothermal
Description : On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)s and the slope of the reversible isothermal line ... Y (C) (∂P/∂V)S = y(∂P/∂V)T (D) (∂P/∂V)S = 1/y(∂P/∂V)T
Last Answer : (C) (∂P/∂V)S = y(∂P/∂V)T
Description : 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)
Last Answer : (C) Both (A) and (B)
Description : In sensible heating or cooling, A. work done remains constant B. dry bulb temperature or air remains constant C. both of the mentioned D. none of the mentioned
Description : The time taken by the machine to attain 0.632 of its final steady temperature rise is called (a) heating time constant (b) cooling time constant (c) either (a) or (b) (d) none of the above
Last Answer : (a) heating time constant
Description : Heating of water under atmospheric pressure is an __________ process. (A) Isochoric (B) Isobaric (C) Adiabatic (D) Isothermal
Last Answer : (B) Isobaric
Description : Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature
Last Answer : (D) Dew point temperature
Description : The expression for entropy change, ΔS = n Cp. ln (T2/T1), is valid for the __________ of a substance. (A) Simultaneous pressure & temperature change (B) Heating (C) Cooling (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : The equilibrium constant for the reversible reaction as shown in the bellow figure, is affected by the (A) Temperature of the system (B) Presence or absence of inerts (C) Pressure of the system (D) Kinetics of the reaction
Last Answer : (C) Pressure of the system
Description : During adiabatic compression of a gas, what is the its temperature?
Last Answer : Rises