Q.1
An ideal gas is initially at P1, V1 is expanded to P2, V2 and then compressed adiabatically to the same volume V1 and pressure PIf W is the net work done by the gas in complete process which of the following is true.. [ IIT 2004]
  • a)W > 0; P3 > P1
  • b) W < 0; P3 > P1
  • c)W > 0; P3 < P1
  • d)W < 0; P3 < P1
Q.2
An ideal gas is expanding such that PT2=constant. The coefficient of volume expansion of the gas is [ IIT 2008]
  • a) 1/T
  • b) 2/T
  • c)3/T
  • d)4/T
Q.3
Which statement is incorrect? [ AIEEE 2002]
  • a) all reversible cycles have same efficiency
  • b) reversible cycles has more efficiency than irreversible one
  • c)carnot cycle is reversible one
  • d)carnot cycle has the maximum efficiency in all cycles
Q.4
Cooking gas container are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will .. [ IIT 2002]
  • a) increase
  • b) decrease
  • c) remain same
  • d) decrease for some, while increase for others
Q.5
At what temperature is the r.m.s. velocity of a hydrogen molecule equals to that of an oxygen molecule at 47°C? [ AIEEE 2002]
  • a) 80 K
  • b) -73K
  • c) 3K
  • d) 20K
Q.6
Even Carnot engine can not give 100% efficiency because we cannot .. [AIEEE 2002]
  • a) prevent radiation
  • b) find ideal sources
  • c) reach absolute zero temperature
  • d) eliminate friction
Q.7
" Heat cannot by itself flow from body at lower temperature to a body at higher temperature" is a statement or consequence of ..[ AIEEE 2003]
  • a) second law of thermodynamics
  • b) conservation of momentum
  • c) conservation of mass
  • d) first law of thermodynamics
Q.8
During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio Cp / Cv for the gas is .. [ AIEEE 2003]
  • a) 4/3
  • b) 2
  • c) 5/3
  • d) 3/2
Q.9
Which of the following parameters does not characterize the thermodynamic state of matter ..[AIEEE 2003]
  • a)temperature
  • b) pressure
  • c)work
  • d)volume
Q.10
A Carnot engine takes 3×106 cal. from a reservoir at 627°C and gives it to sink at 27°C. The work done by the engine is ..[ AIEEE2003]
  • a) 4.2×106J
  • b) 8.4×106J
  • c) 16.8×106J
  • d)zero
Q.11
Which of the following statement is correct for any thermodynamic system? [ AIEEE 2004]
  • a) the change in entropy can naver be zero
  • b) Internal energy and entropy and state functions
  • c)the internal energy changes in all processes
  • d)the work done in an adiabatic process is always zero
Q.12
Two thermally insulated vessel 1 and 2 are filled with air at temperature ( T1 , T2 ), volume (V1, V2 ) and pressure (P1 , P2 ) respectively. If the valve joining the two vessel is opened, the temperature inside the vessel at equilibrium will be [ AIEEE 2004]
  • a)
    ch-12_qn-132choice_img_no1.png
  • b)
    ch-12_qn-132choice_img_no2.png
  • c) T1 + T2
    ch-12_qn-132choice_img_no4.png
  • d)
Q.13
Which of the following is incorrect regarding the first law of thermodynamics? [ AIEEE 2005]
  • a) It is a restatement of the principle of conservation of energy
  • b) It is applicable to any cyclic process
  • c) It introduces the concept of entropy
  • d) It introduces the concept of internal energy
Q.14
A system goes from A to B via two process I and II as shown in figure. If ΔU1 and ΔU2 are the changes in internal energies in the process I and II respectively, then [ AIEEE 2005]
ch-12_que_no-134_img_no1.png
  • a) relation between ΔU1 and ΔU2 can not be determined
  • b) ΔU1 = ΔU2
  • c) ΔU2 < ΔU1
  • d) ΔU2 > ΔU1
Q.15
The temperature -entropy diagram of a reversible engine cycle is given in figure. Its efficiency is [ AIEEE 2005]
ch-12_que_no-135_img_no1.png
  • a) 1/4
  • b) 1/2
  • c) 2/3
  • d) 1/3
Q.16
Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature (7To)/The boxes are then put into thermal contact with each other and heat flows between them until the gases reach a common final temperature ( ignore the heat capacity of boxes). Then, the final temperature of the gases, T in terms of To is ..[ AIEEE 2006]
  • a) Tf = (3To) / 7
  • b) Tf = (7To) / 3
  • c) Tf = (3To) / 2
  • d) Tf = (5To) / 2
Q.17
The work of 146kJ is performed in order to compresses one kilo mole of gas adiabatic ally and in this process the temperature of the gas increased by 7°C. The gas is ( R=8.3 J mol-1K-1) [ AIEEE 2006]
  • a)diatomic
  • b) triatomic
  • c)a mixture of monoatomic and diatomic
  • d)monoatomic
Q.18
When a system is taken from state i to state f along the path iaf, it is found that Q=50 cal and W=20 cal. Along the path ibf Q=36 cal. W along the path ibf is ...[ AIEEE 2007]
ch-12_que_no-138_img_no1.png
  • a) 14 cal
  • b) 6 cal
  • c)16 cal
  • d)66 cal
Q.19
A carnot engine, having an efficiency of η=1/10 s heat engine, is used as refrigerator. If the work done on the system is 10J, the amount of energy absorbed from the reservoir at low temperature is [ AIEEE 2007]
  • a) 100 J
  • b) 99 J
  • c)90 J
  • d)1 J
Q.20
If Cp and Cv denotes the specific heats of nitrogen per unit mass at constant pressure and constant volume respectively then .. [ AIEEE 2007]
  • a) Cp - Cv=28R
  • b) Cp - Cv=R/28
  • c) Cp - Cv=R/14
  • d) Cp - Cv=R
Q.21
One kg of diatomic gas is at a pressure of 8×104N/mThe density of the gas is 4kg/mWhat is the energy of the gas due to thermal motion? [ AIEEE 2009]
  • a)5×104J
  • b) 6×104J
  • c)7×104J
  • d)3×104J
Q.22
At what temperature is the root mean square velocity of gaseous hydrogen molecules equal to that of oxygen molecules at 47°C? [ CPMT 1985]
  • a) 20 K
  • b) 80 K
  • c)-73 K
  • d)3 K
Q.23
A gas at a temperature 250K is contained in a closed vessel. If the gas is heated through 1°C the percentage increase in its pressure is
  • a) 0.4%
  • b) 0.6%
  • c)0.8%
  • d)1.0%
Q.24
The density of a gas is 6×10-2 kg/m3 and the root mean square velocity of the gas molecules is 500 m/s. The pressure exerted by the gas on the walls of the vessel is
  • a) 5×103N/m2
  • b) 1.2×10-4N/m2
  • c) 0.83×10-N/m2
  • d) 30 N/m2
Q.25
N molecules, each of mass m of gas A and 2N molecules, each of mass 2m of gas B are contained in the same vessel at temperature T. The mean square of the velocity of molecules of type B is denoted by v2 and the mean square of the X component of the velocity of A type is denoted by w2, then w2/v2 is :
  • a)2
  • b) 1
  • c)1/3
  • d)2/3
Q.26
A sample of Oxygen gas and a sample of Hydrogen gas both have the same mass, the same volume and the same pressure. The ratio of their absolute temperature is
  • a) 1:4
  • b) 4:1
  • c)1:16
  • d)16:1
Q.27
By what percentage should the pressure of a given mass of gas be increased so as to decrease its volume by 10% at constant temperature?
  • a) 8.1%
  • b) 9.1%
  • c)10.1%
  • d)11.1%
Q.28
At room temperature the r.m.s speed of the molecules of certain diatomic gas is found to be 1930 m/s. The gas is
  • a) H2
  • b) F2
  • c) O2
  • d) Cl2
Q.29
Four molecules of gas are having speeds of 1,4,8 and 16 m/s. the root mean square velocity of the gas molecules is
  • a)7.25 m/s
  • b) 52.56 m/s
  • c)84.25 m/s
  • d)9.2 m/s
Q.30
Two vessels of equal volume contain equal masses of oxygen in one at 400 K. Then the ratio of the r.m.s speed of the molecules of hydrogen to that of the molecules of oxygen is
  • a) 3/4
  • b) 4/3
  • c)2√3
  • d)3√2
0 h : 0 m : 1 s