Engineering Sciences
GATE XE format:mcq PYQs
Build your understanding with focused practice from past exam papers.
Questions 801–810 of 959. Imported answers require independent review unless marked reviewed.
Question 1
Open questionXE-EMCQ1 markNeeds review
When a fixed mass of air-water vapour mixture is heated at constant pressure,
(A) both relative and specific humidity decrease.
(B) relative humidity decreases, but specific humidity remains unchanged.
(C) specific humidity decreases, but relative humidity remains unchanged.
(D) both relative and specific humidity increase.
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For a reversible isothermal expansion of one mole of an ideal gas from state 1 to state 2, the magnitude of work done is
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Open questionXE-EMCQ1 markNeeds review
The statement which is NOT a consequence of the first law of thermodynamics is
(A) Heat is a path function
(B) Energy is a property of a system
(C) Energy of an isolated system is not conserved
(D) A perpetual motion machine of the first kind is not possible
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For a refrigerator absorb heat
from a cold region and rejecting heat
to a hot region, the coefficient of performance is written asYour answerChoose one option.
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The value of the compressibility factor at the critical point evaluated using the van der Waals equation of state is
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The vapour pressure of a liquid at 8 °C is 2.7 kPa. Its enthalpy of vaporization is constant and equal to 4700 kJ/kmol. Take R = 8.314 kJ/kmol.K. The temperature (in °C) at a vapour pressure of 13.5 kPa is
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Open questionXE-EMCQ2 marksNeeds review
Consider the following statements for an ideal gas undergoing a reversible non-flow process:
P. If the process is adiabatic, the change in enthalpy of the gas is necessarily zero.
Q. If the process is adiabatic, the change in entropy of the gas is necessarily zero.
R. If the process is isothermal, the change in enthalpy of the gas is necessarily zero.
S. If the process is isothermal, the change in entropy of the gas is necessarily zero.
Which one of the following options is valid?
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Open questionXE-EMCQ2 marksNeeds review
An ideal Otto cycle (O) and an ideal diesel cycle (D) have the same maximum temperature and reject equal amount of heat. Also, the working fluid enters at the same state before compression. One of the following statements always true about their efficiencies (
) isYour answerChoose one option.
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Open questionXE-EMCQ2 marksNeeds review
A reversible engine receives 75 kJ/s of energy from a reservoir at 750 K and does 12 kJ/s of work. The heat is rejected to two reservoirs at 650 K and 550 K. The rate of heat rejection (in kJ/s) to the reservoir at 650 K is
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Open questionXE-EMCQ2 marksNeeds review
A gas obeys the following equation of state:
where
is molar volume, and
,
are constants with values
J.K/Pa
.kmol and
m
/kmol. Take
kJ/kmol.K. At 10 bar and 500 K, the value of the Joule-Thomson coefficient (in K/Pa) isYour answerChoose one option.
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