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CBSE Questions for Class 11 Engineering Physics Kinetic Theory Quiz 1 - MCQExams.com

An ideal gas goes through a reversible cycle abcd has the V- T diagram shown below. Process da and bc are adiabatic.
The corresponding P-V diagram for the process is ( all figure are schematic and not drawn to scale).
306918.png
In the nuclear fusion reaction, 21H+31H42He + n given that the repulsive potential energy between the two nuclei is 7.7×1014 J, the temperature at which the gases must be heated to initiate the reaction is nearly [Boltzmann's constant k=1.38×1023J/K]
  • 107 K
  • 105 K
  • 103 K
  • 109 K
An ideal gas is enclosed in a cylinder at pressure of 2atm and temperature, 300K. The mean time between two successive collisions is 6×108s. If the pressure is doubled and temperature is increased to 500K, the mean time between two successive collisions will be close to:
  • 4×108s
  • 3×106s
  • 2×107s
  • 0.5×108s
'N' moles of a diatomic gas in a cylinder are at a temperature 'T'. Heat is supplied to the cylinder such that the temperature remains constant but n moles of the diatomic gas gets converted into monatomic gas. What is the change in the total kinetic energy of the gas ?
  • \dfrac{5}{2}nRT
  • \dfrac{1}{2}nRT
  • 0
  • \dfrac{3}{2}nRT
Which of the following shows the correct relationship between the pressure 'P' and density \rho of an ideal gas at constant temperature ? 
Two non-reactive monoatomic ideal gases have their atomic masses in the ratio 2:The ratio of their partial pressures, when enclosed in a vessel kept at a constant temperature, is 4:The ratio of their densities is
  • 1 : 4
  • 1 : 2
  • 6 : 9
  • 8 : 9
A gas molecule of mass M at the surface of the Earth has kinetic energy equivalent to 0^oC. If it were to go up straight without colliding with any other molecules, how high it would rise?
Assume that the height attained is much less than radius of the earth. (k_B is Boltzmann constant)
  • 0
  • \dfrac {273 k_B}{2 Mg}
  • \dfrac {546 k_B}{3 Mg}
  • \dfrac {819 k_B}{2 Mg}
  • Statement -1 is True, Statement-2 is True; Statement -2 is a correct explanation for Statement-1.
  • Statement -1 is True, Statement-2 is True; Statement -2 is NOT a correct explanation for Statement-1.
  • Statement -1 is True, Statement-2 is False
  • Statement -1 is False, Statement-2 is True.
The ratio of the specific heats \dfrac {C_p}{C_v}=\gamma in terms of degree of freedom (n) is given by:
  • \left (1+\dfrac {2}{n}\right )
  • \left (1+\dfrac {n}{2}\right )
  • \left (1+\dfrac {1}{n}\right )
  • \left (1+\dfrac {n}{3}\right )
A given sample of an ideal gas occupies a volume V at a pressure P and absolute temperature T. The mass of each molecule of the gas is m. which of the following gives the density of the gas?
  • mKT
  • P/(kT)
  • Pm/(kT)
  • P/(kTV)
The amount of heat energy required to raise the temperature of 1 g of Helium at NTP, from T_{1}K to T_{2}K is
  • \displaystyle \frac{3}{8}N_{a}k_{B}(T_{2}-T_{1})
  • \displaystyle \frac{3}{2}N_{a}k_{B}(T_{2}-T_{1})
  • \displaystyle \frac{3}{4}N_{a}k_{B}(T_{2}-T_{1})
  • \displaystyle \frac{3}{4}N_{a}k_{B}\left ( \frac{T_{2}}{T_{1}} \right )
Degree of freedom for polyatomic gas is
  • \ge  4
  • \ge  5
  • \ge  6
  • \ge  7
A vessel of volume 20\ L contains a mixture of hydrogen and helium at temperature of 27^{\circ}C and pressure 2\ atm. The mass of mixture is 5\ g. Assuming the gases to be ideal, the ratio of mass of hydrogen to that of the helium in the given mixture will be
  • 1 : 2
  • 2 : 3
  • 2 : 1
  • 2 : 5

The difference between volume and pressure coefficients of an ideal gas is :


24920.PNG
  • \dfrac{1}{273}
  • 273
  • \dfrac{2}{273}
  • Zero
The gas law \left [ \dfrac{PV}{T} \right ]= constant is true for
  • isothermal change only
  • adiabatic change only
  • both isothermal & adiabatic
  • neither isothermal nor adiabatic

The temperature of a gas contained in a closed vessel is increased by 2 K when the pressure is increased by 2%. The initial temperature of the gas is :

  • 200K
  • 100K
  • 200^{0}C
  • 100^{0}C

The mass of oxygen gas (in Kilo grams) occupying a volume of 11.2 litre at a temperature 27^{0}C and a pressure of 76cm of mercury is :

(Molecular weight of oxygen = 32)

  • 0.001456
  • 0.01456
  • 0.1456
  • 1.1456
From what minimum height, a block of ice has to be dropped in order that it may melt completely on hitting the ground :
  • mgh
  • \dfrac{mgh}{l}
  • \dfrac{l}{g}
  • \dfrac{h}{lg}
If for a gas \dfrac{R}{C_{v}}=0.67, then the gas is made up of molecules which are :
  • Diatomic
  • Monoatomic
  • Polyatomic
  • Mixture of Diatomic & Polyatomic

The P-T graph for the given mass of an ideal gas is shown in figure. Then the volume


24918.PNG
  • increases
  • decreases
  • remains constant
  • data insufficient

A gas in an airtight container is heated from 25^{o}C to 90^{o}C. The density of gas will :


24912_3be3ef5bf04d4f9899cb7551ad4cecc0.png
  • increase slightly
  • increase considerably
  • remain the same
  • decrease slightly

The molar gas constant is the same for all gases because at the same temperature and pressure, equal volumes of gases have the same :


24890_63dab1df5b28479dacf92fc02db26c12.png
  • number of molecules
  • average potential energy
  • ratio of specific heats
  • density

If the volume of the gas is to be increased by 4 times :

  • temperature and pressure must be doubled
  • at constant P, the temperature must be increased by 4 times
  • at constant T, the pressure must be increased by 4 times
  • it cannot be increased

Three closed vessels A, B and C are at the same temperature T and contain gases which obey Maxwell distribution law of velocities. Vessel A contains O_2, B only N_2 and C mixture of equal quantities of O_2 and N_2. If the average speed of O_2 molecules in vessel A is V_1 and that of N_1 molecules in vessel B is V_2, then the average speed of the O_2 molecules in vessel C is

  • \frac{{({v_1} + {v_2})}}{2}
  • V_1
  • \sqrt {{v_1}{v_2}}
  • None of these

A gas at temperature 27^{0}C and pressure 30 atmospheres is allowed to expand to one atmospheric pressure. If the volume becomes 10 times its initial volumes, the final temperature becomes :

  • 100^{o}C
  • 373 K
  • 373^{o}C
  • -173^{o}C

The Universal gas constant may be expressed as :

a) 8.31 J/mole-K         c) 2.00 J/mole-K

b) 8.31 cal/mole-K       d) 2.00 cal/mole-K

  • a,c
  • a,d
  • b,c
  • b,d

The parameter that determine the physical state of gas are :

a) Pressure                  b) Volume

c) Number of moles    d) Temperature

  • a & b
  • a,b & c
  • a,b & d
  • a,c & d
State whether true or false.
The arrangement of particles in a liquid is less ordered compared to solids. However, there is no order in the arrangement of particles in the gaseous state.
  • True
  • False

16 gm of O_{2} gas and x gm of H_{2} gas occupy the same volume at the same temperature and pressure. Then x is :

  • 1/2gm
  • 1gm
  • 8gm
  • 16 gm

Select the correct formula :

(where k=Boltzmann's constant, R= gas constant, n= moles, r = density, M= molecular weight, p= pressure, T= kelvin temperature, V= volume)

a) k=RN_{av}

b)r=\dfrac{nM}{V}

c)\dfrac{p}{r}=\dfrac{RT}{M}

d) R=kN_{av}

  • a,b,c
  • a,b,d
  • b,c,d
  • a,c,d

In the equation PV=constant, the numerical value of constant depends upon

a) temperature                 b) mass of the gas

c) system of units used   d) nature of the gas

  • a & b
  • b & c
  • c & d
  • all
State whether true or false.
Sponge though compressible, is a solid.
  • True
  • False

Two containers of equal volume containing the same gas at pressure P_{1} and  P_{2} and absolute temperature  T_{1} and  T_{2} respectively were connected with narrow capillary tube. The gas reaches a common pressure P and a common temperature T. The ratio P/T is equal to :

  • \dfrac{P_{1}}{T_{1}} +\dfrac{P_{2}}{T_{2}}
  • \dfrac{1}{2}\left ( \dfrac{P_{1}}{T_{1}} +\dfrac{P_{2}}{T_{2}}\right )
  • \dfrac{P_{1}T_{2}+P_{2}T_{1}}{T_{1}+T_{2}}
  • \dfrac{P_{1}T_{2}-P_{2}T_{1}}{T_{1}-T_{2}}
The value of \gamma for gas X is 1.66, then x is :
  • Ne
  • O_3
  • N_2
  • H_2
According to the Boltzmann's law of equipartition of energy, the energy per degree of freedom and at a temperature T K is :
  • (3/2) KT
  • (2/3) KT
  • KT
  • 1/2 KT
When the pressure of a gas is changed, then:
  • The density of the gas also changes.
  • The ratio of the pressure to the density remains unaffected.
  • The velocity of the sound remains unaffected.
  • The value of \gamma changes.
A system consists of N particles, which have independent K relations among one another. The number of degrees of freedom of the system is given by :
  • 3 NK
  • N/3K
  • 3 N/K
  • 3N - K
The value of C_v for 1 mol of polyatomic gas is (F = number of degrees of freedom) :
  • \displaystyle \frac{fR}{2T}
  • \displaystyle \frac{fR}{2}
  • \displaystyle \frac{fRT}{2}
  • 2fRT
A man is climbing up a spiral type staircase. His degrees of freedom are :
  • 1
  • 2
  • 3
  • more than 3
The law of equipartition of energy was given by :
  • Claussius
  • Maxwell
  • Boltzmann
  • Carnot
If the number of molecules in a gas is N then the number of molecules moving in negative X-direction will be :
  • N/6
  • N/4
  • N/3
  • N
At what temperature will the kinetic energy of gas molecules be double of its value at 27^oC?
  • 54^oC
  • 108^oC
  • 300^oC
  • 327^oC
The internal energy of a monoatomic ideal gas is :
  • only kinetic
  • only potential
  • partly kinetic and partly potential
  • none
Keeping the number of moles, volume and temperature the same, which of the following are the same for all ideal gases?
  • rms speed of molecules
  • Density
  • Pressure
  • Average magnitude of momentum
Which of the following is/are true on the basis of kinetic theory of matter?

  • Solids have a definite volume and definite shape
  • Liquids have a definite volume, but no definite shape
  • Gases have no definite volume and no definite shape
  • All of the above
Solids have :
  • definite mass
  • definite volume
  • both A & B
  • none
The amount of heat required to heat 1 mol of a monoatomic gas from 200^oC to 250^oC will be ............. if the heat required to heat the diatomic gas from 200^oC to 300^oC is Q.
  • 2Q/3
  • 3Q/5
  • 3Q/10
  • 2Q/5
On the basis of kinetic theory of matter :
  • the solids have a definite volume and definite shape
  • the liquids have a definite volume but no definite shape
  • the gases have no definite volume and no definite shape
  • all of the above 
The inter-molecular spaces in a liquid is :
  • less than a solid
  • more than a gas
  • more than a solid
  • more than a solid and a gas
The correct relation connecting the universal gas constant (R), Avogadro number N_A and Boltzmann constant (K) is :
  • R = NK^2
  • K = NR
  • N = RK
  • R=NK
0:0:1


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