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CBSE Questions for Class 11 Engineering Physics Kinetic Theory Quiz 13 - MCQExams.com

In Maxwell's speed distribution curve, for N2N2K will be?
  • 300 m/sec
  • 606 m/sec
  • 920 m/sec
  • Zero
For which of the following ideal gas CV,m is independent of temperature?
  • He
  • H2
  • CO
  • SO2
At constant pressure, the heat of formation of a compound is not dependent on temperature, when: 
  • ΔCp=0
  • ΔCv=0
  • ΔCp>0
  • ΔCp<0
Pressure of an ideal gas is increased by keeping temperature constant. The kinetic energy of molecules.
  • Decreases
  • Increases
  • Remains same
  • Increases or decreases depending on the nature of gas
A quantity of 10g of a gas at 1 atm pressure is cooled from 273oC to 273K keeping its volume constant, the final pressure of the gas will be?
  • 273 atm
  • 0.5 atm
  • 0.2 atm
  • 0.1 atm
If the temperature of 3 moles of helium gas is increased by 2 K, then the change in the internal energy of helium gas is :
  • 70.0 J
  • 68.2 J
  • 74.8 J
  • 78.2 J
In the case of solid, number of degrees of freedom is :
  • 3
  • 5
  • 6
  • 7
The average kinetic energy of a gas molecule at 27oC is 6.21×1021 J. Its average kinetic energy at 227oC will be :
  • 52.2×1021 J
  • 5.22×1021 J
  • 10.35×1021 J
  • 11.35×1021 J
The curve in figure represents potential energy(U) in between two atoms in a diatomic molecule as a function of distance 'x' between atoms. The atoms are:
1703278_01390d801a4a4d7ea60a13e2a2e51b58.png
  • Attracted when x lies between 'A' and 'B' and repelled when x lies between B and C
  • Attracted when x lies between B and C and repelled when x lies between A and B
  • Attracted when they reach B
  • Repelled when they reach B
Reducing the pressure from 1.0 atm to 0.5 atm would change the number of molecules in one mole of ammonia to?
  • 75% of initial value
  • 50% of initial value
  • 25% of initial value
  • None of these
At what temperature the KE of gas molecule is half that of its volue at 27oC?
  • 13.5oC
  • 150oC
  • 150 K
  • 123 K
The average translation kinetic energy of O2 (molar mass 32) molecules at a particular temperature is 0.048 eV. The translational kinetic energy of N2 (molar mass 28) molecules in eV at the temperature is :
  • 0.0015
  • 0.003
  • 0.048
  • 0.768
The quantity PVkT represents
  • mass of the gas
  • kinetic energy of the gas
  • number of moles of the gas
  • number of molecules in the gas
Which of the following parameters is the same for molecules of all gases at a given temperature?
  • Mass
  • Speed
  • Momentum
  • Kinetic energy
The heat capacity of air is 20 J/K/mol. The amount of heat, required to heat the room through 1o, assuming the amount of air in the room to be 29 kg, is
  • 20 kJ
  • 20 J
  • 200 J
  • 200 kJ
In Fig. here shows four paths traversed by a gas on a P-V diagram. If ΔU1,ΔU2,ΔU3 and ΔU4 are the change in internal energies in their respective path, then choose the incorrect relation:
1740409_550dcff423234db9adb771dde3f0e4d6.PNG
  • ΔU1=ΔU2=ΔU4=ΔU3
  • ΔU1+ΔU2=ΔU3+ΔU4
  • ΔU1>ΔU2>ΔU3>ΔU4
  • ΔU1<ΔU2<ΔU3<ΔU4
The energy density U / V of an ideal monoatomic gas is related to its pressure P as
  • UV=3P
  • UV=32P
  • UV=P3
  • UV=52P
The ratio of average translational kinetic energy to rotational kinetic energy of a diatomic molecule at temperature T is : 
  • 3
  • 7/5
  • 5/3
  • 3/2
Find the approx. number of molecules contained in a Vessel of volume 7 litres at 00C at 1.3×105 pascal:
  • 2.4×1023
  • 3.0×1023
  • 6.0×1023
  • 4.8×1023
Heat is added to an ideal gas and the gas expands. In such a process the temperature: 
  • must always increase
  • will remain the same if the work done equals the hear added
  • must always decrease
  • will remain the same if change in internal energy equals the heat added
Select the correct statements about ideal gas: 
  • Molecules of a gas are in random motion colliding against one another and with the walls of the container
  • The gas is not isotropic and the constant (1/3) in equation p=13pv2 r. m. s. is result of this property
  • The time during which a collision lasts is negligible compared to the time of free path between collisions
  • There is no force of interaction between molecules among themselves or between molecules and the wall except during collision.
An ideal gas undergoes the cyclic process shown in a graph below
1749708_4824e05c68504739b89d3f2e43ddc19a.PNG
  • T1=T2
  • T1>T2
  • VaVc=VbVd
  • VaVb=VcVd
A lead bullet just melts when stopped by an obstacle. Assuming that 25% of heat is absorbed by the obstacle, find the minimum velocity of the bullet if its initial temperature is 270C (melting point of lead 3270C; specific heat of lead =0.03 cal/g0C; latent heat of fusion of lead = 6 cal/g and J = 4.2 J/cal)
  • 450 m/s
  • 398 m/s
  • 420 m/s
  • 410 m/s
Postulate of kinetic theory is
  • Atom is indivisible
  • Gases combine in a simple ratio
  • There is no influence of gravity on the molecules of a gas
  • None of the above
If Cv = 4.96 cal / mole K, then increase in internal energy when temperature of 2 moles of this gas is increased from 340 K to 342 K
  • 27.80 cal
  • 19.84 cal
  • 13.90 cal
  • 9.92 cal
The temperature of an ideal gas is kept constnat as it expands. The gas does external work. During this process, the internal energy of the gas
  • Decreases
  • Increases
  • Remains constant
  • Depend on the molecular motion
Molecules of a gas behave like 
  • Inelastic rigid sphere
  • Perfectly elastic non-rigid sphere
  • Perfectly elastic rigid sphere
  • Inelastic non-rigid sphere
Heat is not being exchanged in a body. If its internal energy is increased then
  • Its temperature will increase
  • Its temperature will decrease
  • Its temperature will remain constant
  • None of these
The internal energy of an ideal gas depends upon
  • Specific volume
  • Pressure
  • Temperature
  • Density
The degrees of freedom of a stationary rigid body about its axis will be 
  • One
  • Two
  • Three
  • Four
The pressure exerted by the gas on the walls of the container because
  • It loses kinetic energy
  • It sticks with the walls
  • On collision with the walls there is a change in momentum
  • It is increased towards the walls
The number of translational degrees of freedom for a diatomic gas is 
  • 2
  • 3
  • 5
  • 6
A monoatomic gas molecules has 
  • Three degrees of freedom
  • Four degrees of freedom
  • Five degrees of freedom
  • Six degrees of freedom
The degrees of freedom of a triatomic gas is 
  • 2
  • 4
  • 6
  • 8
At a given volume and temperature , the pressure of a gas
  • Varies inversely as its mass
  • Varies inversely as the square of its mass
  • Varies linearly as its mass
  • Is independent of its mass
A diatomic molecules has how many degrees of freedom 
  • 3
  • 4
  • 5
  • 6
In an ideal gas, the molecules possess
  • only kinetic energy
  • both kinetic energy and potential energy
  • only potential energy
  • neither kinetic energy nor potential energy
The mean kinetic energy of a gas at 300K is 100J. The mean energy of the gas at 450K is equal to 
  • 100J
  • 3000J
  • 450J
  • 150J
Mean kinetic energy per degree of freedom of gas molecules is 
  • 32kT
  • kT
  • 12kT
  • 32RT
On colliding in a closed container the gas molecules 
  • Transfer momentum to the walls
  • Momentum becomes zero
  • Move in opposite directions
  • Perform Brownian motion
A thin walled hollow cylinder is rolling down an incline , without slipping. At any instant, without slipping. At any instant the ratio "Rotational K.E : Translational K.E : Total K.E" is 
  • 1:1:2
  • 1:2:3
  • 1:1:1
  • 2:1:3
According to the law of equipartition of energy, the energy associated with each degree of freedom is:
  • 13KBT
  • 12KBT
  • KBT
  • 32KBT
A 90 cm long barometer tube contains some air above the mercury. The reading is 74.5 cm when the true pressure is 76 cm at the temperature 150C. If the reading is observed to be 75.8 cm on a day when the temperature is 50C, then the true pressure is:
  • 77.38 cm of Hg
  • 75.8 cm of Hg
  • 74 cm of Hg
  • 80 cm of Hg
Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of N2 at temperature T0, while box B contains one mole of H2 at temperature 7/3 T0. 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 Tf in terms of T0 is
  • Tf=52To
  • Tf=37To
  • Tf=53To
  • Tf=32To
Internal energy of n1 moles of H2 at temperature T is equal to the internal energy of n2 moles of He at temperature 2T. Then the ratio n1n2 is
  • 3/5
  • 2/3
  • 6/5
  • 3/7

A closed container of volume 0.02 m3 contains a mixture of neon and argon gases at a temperature of 270 C and at a pressure of 1×105N/m2. The total mass of the mixture is 28 g. If the gram molecular weights of neon and argon are 20 and 40 respectively, the masses of the individual gases in the container are respectively(assuming them to be ideal) [R = 8.314 J/mol K]

  • 16 gm, 12 gm
  • 4 gm, 24 gm
  • 6 gm, 22 gm
  • 12 gm, 16 gm
A current passes through a resistor. Let K1 and K2 represent the average kinetic energy of the conduction electrons and the metal ions respectively, then:
  • K1 < K2
  • K1=K2
  • K1 > K2
  • Any of these 3 may be correct
A smooth vertical tube with two different cross-sections is open at both ends. They are fitted with  pistons of different areas of cross- section and each  piston moves within a particular section. One mole of a gas enclosed between the pistons which are tied with non-stretchable threads. The difference  in cross-sectional area of  pistons 10cm2 The mass of gas confined between  pistons is  5kg. The outside  pressure is 1 atmosphere=105N/m2. By how many degrees must the gas between pistons be heated to shift the piston by 5 cm?
Given R=8.3.

44600_eef179723d964031bc2768fe2f142c38.png
  • 0.9oC
  • 1.2oC
  • 1.5oC
  • 0.5oC

A horizontal uniform glass tube of 100cm length is sealed at both ends contains 10 cm mercury column in the middle the temperature and pressure of air on either side of mercury column are respectively 310C and 76cm of mercury if the air column at one end is kept at 00C and the other end at 2730C the pressure of air which is at 00C is (in cm of Hg )

  • 76
  • 88.2
  • 102.4
  • 122

Two identical containers each of volume V0 are joined by a small pipe. The containers contain identical gases at temperature T0 and pressure P0. One container is heated to temperature 2T0 while maintaining the other at the same temperature. The common pressure of the gas is P and n is the number of moles of gas in container at temperature 2T0.

  • P=2P0
  • P=43P0
  • n=2P0V03RT0
  • n=3P0V02RT0
0:0:1


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