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Set 8 of 8 · Questions 211-229 of 229

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JEE Main Physics · Kinetic Theory of Gases · Set 8 (Q211-229)

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  1. 211.
    The number of vibrational degrees of freedom of a diatomic molecule is
    1. (1)0
    2. (2)1
    3. (3)2
    4. (4)3
  2. 212.
    A flask contains argon and oxygen in the ratio of 3:2 in mass and the mixture is kept at 27°C. The ratio of their average kinetic energy per molecule respectively will be :
    1. (1)3 : 2
    2. (2)9 : 4
    3. (3)2:3
    4. (4)1 : 1
  3. 213.
    The rms speeds of the molecules of Hydrogen, Oxygen and Carbondioxide at the same temperature are and respectively then :
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  4. 214.
    A gas has n degrees of freedom. The ratio of specific heat of gas at constant volume to the specific heat of gas at constant pressure will be :
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  5. 215.
    If one mole of an ideal gas at is allowed to expand reversibly and isothermally ( to ) its pressure is reduced to one-half of the original pressure (see figure). This is followed by a constant volume cooling till its pressure is reduced to one-fourth of the initial value . Then it is restored to its initial state by a reversible adiabatic compression ( to ). The net workdone by the gas is equal to :
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  6. 216.
    At 300 K, the rms speed of oxygen molecules is times to that of its average speed in the gas. Then, the value of will be (used )
    1. (1)32
    2. (2)28
    3. (3)24
    4. (4)27
  7. 217.
    The internal energy (U) and the density (ρ) of an ideal gas follow the law Uρ = constant during a particular process. The same process will be correctly shown on a P–U diagram as -
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  8. 218.
    Two perfectly black spheres and having radii and are maintained at temperatures and respectively. The ratio of the energy radiated by to that by is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  9. 219.
    For a gas having ' ' degrees of freedom, ' ' is ratio of specific heats
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  10. 220.
    The pressure exerted by an ideal gas at a particular temperature is directly proportional to
    1. (1)the mean speed of the gas molecules
    2. (2)mean of the square of the speed of the gas molecules
    3. (3)the square of the mean speed of the gas molecules
    4. (4)the root mean square speed of the gas molecules.
  11. 221.
    If R is universal gas constant, the amount of heat needed to raise the temperature of 2 moles of an ideal monoatomic gas from 273 K to 373 K when no work is done is -
    1. (1)100 R
    2. (2)150 R
    3. (3)300 R
    4. (4)500 R
  12. 222.
    The root mean square speed of smoke particles of mass 5 x kg in their Brownian motion in air at NTP is approximately. [Given k = 1.38 x ]
    1. (1)60 mm
    2. (2)12 mm
    3. (3)
    4. (4)
  13. 223.
    Choose the correct graph of ideal gas for given - graph.
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  14. 224.
    A partition divides a container having insulated walls into two compartments I and II. The same gas fills the two compartments (shown in figure). The ratio of the number of molecules in compartments I and II is–
    1. (1)1 : 6
    2. (2)6 : 1
    3. (3)4 : 1
    4. (4)1 : 4
  15. 225.
    If the rms speed of oxygen molecules at is 160m/s, find the rms speed of hydrogen molecules at .
    1. (1)640m/s
    2. (2)40m/s
    3. (3)80m/s
    4. (4)332m/s
  16. 226.
    What will be the effect on the root mean square velocity of oxygen molecules if the temperature is doubled and oxygen molecule dissociates into atomic oxygen?
    1. (1)The velocity of atomic oxygen remains same
    2. (2)The velocity of atomic oxygen doubles
    3. (3)The velocity of atomic oxygen becomes half
    4. (4)The velocity of atomic oxygen becomes four times
  17. 227.
    The relation between root mean square speed () and most probable speed () for the molar mass M of oxygen gas molecule at the temperature of 300 K will be :-
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  18. 228.
    According to kinetic theory of gases,
    A. The motion of the gas molecules freezes at 0°C
    B. The mean free path of gas molecules decreases if the density of molecules is increased.
    C. The mean free path of gas molecules increases if temperature is increased keeping pressure constant.
    D. Average kinetic energy per molecule per degree of freedom is T (for monoatomic gases)
    Choose the most appropriate answer from the options given below:
    1. (1)A and C only
    2. (2)B and C only
    3. (3)A and B only
    4. (4)C and D only
  19. 229.
    At a certain temperature, the degrees of freedom per molecule for gas is 8. The gas performs 150 J of work when it expands under constant pressure. The amount of heat absorbed by the gas will be .........J.