Q.1
A carnot engine uses first an ideal monoatomic gas ( γ=5/3) and then ideal diatomic gas ( γ=7/5) as its working substance. The source and sink temperature are 411°C and 69°C respectively and the engine extract 1000J of heat from the source in each cycle. Then.. [ CPMT 1998]
  • a) The efficiencies of the engine in the two cases are in ratio 21:25
  • b) The area enclosed by the PV diagram in the first case only 500J
  • c) The area enclosed by the PV diagram in both cases is 500J
  • d)The heat energy rejected by the engine in the first case is 600J while that in the second case is 741.3J [ CPMT 1998]
Q.2
The specific heat of 1 mole of an ideal gas at constant pressure is represented by Cp and that at constant volume by Cv. One of the following statement is correct [ MNR 1992]
  • a) Cp of hydrogen gas is 5R/2
  • b) Cv of hydrogen is 7R/2
  • c) H2 has a very small value of Cp and Cv
  • d) Cp -Cv=1.99 cal/ mole K for H2
Q.3
A gas undergoes a process, changing from its initial state to some other state. Which of the following does not depend only on the initial and final states but also on the path followed
  • a)heat exchanged with systems
  • b) Internal energy
  • c)entropy
  • d)none of the above
Q.4
A gas undergoes a change at constant temperature. Which of the following quantities remains fixed?
  • a) Pressure
  • b) Entropy
  • c)Heat exchanged with the system
  • d)All the above may change
Q.5
A gas does 4.5 J of external work during adiabatic expansion. Its temperature falls by 2K. Its internal energy will
  • a) Increase by 4.5J
  • b) Decrease by 4.5J
  • c)Decrease by 2.25J
  • d)Decrease by 9J
Q.6
An ideal gas is isothermally expanded. Its internal energy will [ CPMT 1990]
  • a) increase
  • b) decrease
  • c) increase or decrease depending upon the nature of gas
  • d) remains same
Q.7
The difference between Cp and Cv is ...
  • a)zero for solids and liquids
  • b) same for solids, liquid and gases
  • c)positive for solids, liquids and gases
  • d)more for 1 gm molecules of oxygen than for 1 gm molecule of hydrogen
Q.8
When 1g water freezes at at 0°C and 1×105N/m2 pressure, it is converted into 1.091 cc ice at 0°C. The external work done nearly
  • a) +0.0091 J
  • b) -0.0091J
  • c)+0.0182J
  • d)-0.0182J
Q.9
When a gas is heated at constant pressure, the percentage of heat energy supplied, which goes as the internal energy of the gas is ..
  • a) more for a diatomic gas for a monoatomic gas
  • b) same for monoatomic, diatomic and triatomic gases
  • c)100% for all gas
  • d)less for a triatomic gas than for a diatomic gas
Q.10
The molar specific heat of oxygen at constant pressure, Cp=7.03 Cal mole-1°C-1 and R=8.31 Joule mole-1°C-The amount of heat taken by 5 mole of oxygen when heated at constant volume from 10°C to 20°C will be approximately [ MPPMT 1987]
  • a) 25 cal
  • b) 50 cal
  • c) 250 cal
  • d) 500 cal
Q.11
A bullet travelling with velocity 100 m/sec hits a concrete wall. All its kinetic energy is converted into heat energy in the bullet with the result that there is an increase of 50°C in the temperature of the bullet. What will be the increase in the temperature if the bullet were travelling with a velocity 200 m/sec?
  • a)100°C
  • b) 50°C
  • c)200°C
  • d)400°C
Q.12
Carbon monoxide is carried around a closed cycle abc, in which bc is an isothermal process, as shown in the figure. The gas absorbs 7000J of heat, as its temperature increases from 300K to 1000 K in going from a to b. The quantity of heat rejected by the gas during the process ca is ..[ SCRA 1994]
ch-12_que_no-102_img_no1.png
  • a) 4200 J
  • b) 5000 J
  • c)9800 J
  • d)-9800 J
Q.13
A bullet made of lead moving with velocity v hits a wall. Its 50% kinetic energy is converted into heat, then increase in temperature will be... [ Raj.PMT 1996]
  • a) 2v2 / JS
  • b) v2 / 4JS
  • c)v2S / J
  • d)v2S / 2J
Q.14
The molar specific heat of an ideal gas at constant pressure and volume are denoted by Cp and Cv respectively. Further Cp/Cv=γ and R is the gas constant for 1gm of gas. Then Cv is equal to ...
  • a) R
  • b) γR
  • c) R / (γ-1)
  • d) γR / (γ-1)
Q.15
If the ratio of specific heat of gas at constant pressure to that at constant volume is γ, the change in internal energy of a mass of gas when the volume change from V to 2V at constant pressure P is .. [ CBSE 1998]
  • a)R / ( γ -1)
  • b) PV
  • c)PV / (γ-1)
  • d)γPV / (γ-1)
Q.16
The specific heat of hydrogen gas at constant pressure is Cp=3.4×103 calories /kg°C and at constant volume is Cv=2.4×103 calories/ kg°C. If one kilogram hydrogen is heated from 10°C to 20°C at constant pressure, the external work done on the gas to maintain it at constant pressure is [ MPPMT 1995]
  • a) 103 calories
  • b) 5 ×103 calories
  • c)104 calories
  • d)105 calories
Q.17
Fig. below represents a cyclic process abca for one mole of an ideal gas. If ab is isothermal process then which of the following is the P-T diagram for the cyclic process
ch-12_que_no-107_img_no1.png
  • a)
    ch-12_qn-107choice_img_no1.png
  • b)
    ch-12_qn-107choice_img_no2.png
  • c)
    ch-12_qn-107choice_img_no3.png
  • d)
    ch-12_qn-107choice_img_no4.png
Q.18
A constant volume gas thermometer works on [ IIT 1980]
  • a) The principle of Archimedes
  • b) Boyle's law
  • c) Pascal's law
  • d) Charles' law
Q.19
An ideal monoatomic gas is taken round the cycle ABCDA as shown in the P_V diagram. The work done during the cycle is .. [ IIT 1983]
ch-12_que_no-109_img_no1.png
  • a)PV
  • b) 2PV
  • c)½ PV
  • d)zero
Q.20
One mole of a monoatomic gas ( γ=5/3) is mixed with one mole of a diatomic gas ( γ=7/5), the value of γ for mixture is .. [ IIT 1988]
  • a) 1.4
  • b) 1.5
  • c)1.53
  • d)3.07
Q.21
From the following statements ideal gas at any given temperature T, select the correct one [ IIT 1995]
  • a) The coefficient of volume expansion at constant pressure is the same for all ideal gases
  • b) The average translational kinetic energy per molecule of oxygen gas is 3kT, k is being Boltzmann constant
  • c)The mean free path of molecules increases with increase in the pressure
  • d)In gaseous mixture, the average translational kinetic energy of the molecules of each component is different
Q.22
A closed compartment containing gas is moving with some acceleration in horizontal direction. Neglect effect of gravity. Then the pressure in the compartment is ..[ IIT 1999]
  • a) same everywhere
  • b) lower in the front side
  • c) lower in te rear side
  • d) lower in the upperside
Q.23
A gas mixture consists of 2 moles of oxygen and 4 moles of argon at temperature T. Neglecting all vibrational modes, the total internal energy of the system is [ IIT 1999s]
  • a)4 RT
  • b) 15 RT
  • c)9 RT
  • d)11 RT
Q.24
A monoatomic ideal gas, initially at temperature T1 is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature T2 by releasing the piston suddenly. If L1 and L2 are the length of the gas column before and after expansion respectively, then T1 / T2 is given by .. [ IIT 2000]
  • a)
    ch-12_qn-114choice_img_no1.png
  • b)
    ch-12_qn-114choice_img_no2.png
  • c)
    ch-12_qn-114choice_img_no3.png
  • d)
    ch-12_qn-114choice_img_no4.png
Q.25
An ideal gas is initially at temperature T and volume V. Its volume is increased by ΔV due to an increase in temperature ΔT, pressure remains constant. The quantity δ=ΔV / ( VΔT) varies with temperature as .. [ IIT 2000]
  • a)
    ch-12_qn-115choice_img_no1.png
  • b)
    ch-12_qn-115choice_img_no2.png
  • c)
    ch-12_qn-115choice_img_no3.png
  • d)
    ch-12_qn-115choice_img_no4.png
Q.26
In a given process on an ideal gas, dW=0 and dQ
  • a) the temperature will decrease
  • b) the volume will increase
  • c) the pressure will remain constant
  • d) the temperature will increase
Q.27
P-V plots for two gases during adiabatic process are shown in the figure. Plot 1 and 2 should correspond respectively to .. [ IIT 2001]
ch-12_que_no-117_img_no1.png
  • a)He and O2
  • b) O2 and He
  • c)He and Ar
  • d)O2 and N2
Q.28
Which of the following graph correctly represents the variation of with P for an ideal gas at constant temperature? [ IIT 2002]
ch-12_que_no-118_img_no1.png
  • a)
    ch-12_qn-118choice_img_no1.png
  • b)
    ch-12_qn-118choice_img_no2.png
  • c)
    ch-12_qn-118choice_img_no3.png
  • d)
    ch-12_qn-118choice_img_no4.png
Q.29
The PT diagram for an ideal gas is shown in figure, where AC is an adiabatic process, find the corresponding PV diagram ..[ IIT 20003]
ch-12_que_no-119_img_no1.png
  • a)
    ch-12_qn-119choice_img_no1.png
  • b)
    ch-12_qn-119choice_img_no2.png
  • c)
    ch-12_qn-119choice_img_no3.png
  • d)
    ch-12_qn-119choice_img_no4.png
Q.30
If liquefied oxygen at 1 atmospheric pressure is heated from 50K tp 300K by supplying heat at constant rate. The graph of temperature vs time will be ..[ IIT 2004]
  • a)
    ch-12_qn-120choice_img_no1.png
  • b)
    ch-12_qn-120choice_img_no2.png
  • c)
    ch-12_qn-120choice_img_no3.png
  • d)
    ch-12_qn-120choice_img_no4.png
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