Heat and Work | Thermodynamics | GATE MCQs (Solved)

GATE ME solved Questions on Heat and work(Thermodynamics)


Question #1

Which of the following statements are TRUE with respect to heat and work?
(i) They are boundary phenomena
(ii) They are exact differentials
(iii) They are path functions
(A) both (i) and (ii)

(B) both (i) and (iii)

(C) both (ii) and (iii)

(D) only (iii)

[GATE 16 S1, 1 mark]


Question #2

An ideal gas undergoes a reversible process in which the pressure varies linearly with volume. The conditions at the start (subscript 1) and at the end (subscript 2) of the process with usual notation are: P1 = 100 kPa, 𝑉1 = 0.2 m3 and P2 = 200 kPa, 𝑉2 = 0.1 m3 and the gas constant, R = 0.275 kJ/kg-K. The magnitude of the work required for the process (in kJ) is ________

[GATE 16 S1, 2 marks]


Question #3

A mixture of ideal gases has the following composition by mass:

N2 O2 CO2
60% 30% 10%

If the universal gas constant is 8314 J/kmol-K, the characteristic gas constant of the mixture (in J/kg-K) is ________

[GATE 15 S3, 2 marks]


Question #4

A cylinder contains 5 m3 of an ideal gas at a pressure of 1 bar.This gas  is compressed in a reversible isothermal process till its pressure increases to 25 bar. the work in kJ for this process is

[GATE 13, 1 mark]

(a)804.7

(b)953.2

(c)981.7

(d)1012.2


Question #5

The contents of a well insulated tank are heated by a resistor of 23 $\Omega$ in which 10 A current is flowing. Consider the tank along with its contents as a thermodynamic system.The work done by the system and the heat transfer are positive.the rates of heat(Q), work(W) and change in internal energy(\Delta U) during the process in kW are

(A) Q=0, W= – 2.3 , $\Delta U=+2.3$

(B) Q= +2.3, W= 0 , $\Delta U=+2.3$

(C) Q= -2.3, W= 0, $\Delta U= – 2.3$

(D) Q=0, W= + 2.3 , $\Delta U= – 2.3$

[GATE 2011, 1 mark]


Question #6

Heat and work are

(A) intensive properties

(B) extensive properties

(C) point function

(D) path function

[GATE 2011, 1 mark]


Question #7

A pump handling a liquid raises its pressure from 1 bar to 30 bar. Take the densilty of the liquid as 990kg/m.The isentropic specific work done by the pump in kJ/kg is

(A) 0.10

(B) 0.30

(C) 2.50

(D) 2.93

[GATE 2011, 1 mark]


Question #8

A monatomic ideal gas($\gamma=1.67$, Molecular Weight=40) is compressed adiabatically from 0.1 Mpa, 300K to 0.2 Mpa. Universal gas constant is 8.314 kJ k mol-1K-1 the work of compression of the gas(in kJ kg-1) is

[GATE 2010, 2 marks]

(a)29.7

(b)19.9

(c)13.3

(d)0


Question #9

A compressor undergoes a reversible, steady flow process.The gas at inlet and outlet of the compressor is designated as state 1 and 2 respectively.Potential and kinetic energy changes are to be ignored.The following notations are used : v=specific volume and P=pressure of the gas.The specific work required to be supplied to the compressor for this gas compression process is

(A) $\int ^2 _1Pdv$

(B) $\int ^2 _1vdP$

(C) $v_1(P_2-P_1)$

(D) $-P_2(v_1-v_2)$

[GATE 2009, 1 mark]


Question #10

A frictionless piston-cylinder device contains a gas initially at 0.8 MPa and 0.015m3. It expands quasistatically at constant temperature to final volume of 0.030 m3. The work output(in kJ) during the process will be,

(A) 8.32

(B) 12.00

(C) 554.67

(D) 8320.00

[GATE 2009, 2 marks]

 

Ask your doubts in the comment section below

 

Practice other topics from Thermodynamics:

Basics of thermodynamics

First law of thermodynamics

Second law of thermodynamics

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