Kinetic Theory Physics - Kinetic Theory

In a diatomic molecule, the rotational energy at a given temperature.

1. Obeys Maxwell’s distribution.
2. Have the same value for all molecules.
3. Equals the translational kinetic energy for each molecule.
4. Is (2/3)rd the translational kinetic energy for each molecule.

When an ideal gas is compressed adiabatically, its temperature rises the molecules on the average have more kinetic energy than before. The kinetic energy increases,

1. Because of collisions with moving parts of the wall only.
2. Because of collisions with the entire wall.
3. Because the molecules gets accelerated in their motion inside the volume.
4. Because of redistribution of energy amongst the molecules.

ABCDEFGH is a hollow cube made of an insulator (figure) face A BCD has positive charge on it. Inside the cube, we have ionised hydrogen. The usual kinetic theory expression for pressure.

1. Will be valid.
2. Will not be valid, since the ions would experience forces other than due to collisions with the walls.
3. Will not be valid, since collisions with walls would not be elastic.
4. Will not be valid because isotropy is lost.

Boyle’s law is applicable for an:

1. Diabatic process.
2. Isothermal process.
3. Isobaric process.
4. Isochoric process.

1 mole of an ideal gas is contained in a cubical volume V, ABCDEFGH at 300K (figure). One face of the cube (EFGH) is made up of a material which totally absorbs any gas molecule incident on it. At any given time,

1. The pressure on EFGH would be zero.
2. The pressure on all the faces will be equal.
3. The pressure of EFGH would be double the pressure on ABCD.
4. The pressure on EFGH would be half that on ABCD.

Calculate the ratio of the mean free paths of the molecules of two gases having molecular diameters 1 A and 2 A. The gases may be considered under identical conditions of temperature, pressure and volume.

Calculate the number of atoms in 39.4g gold. Molar mass of gold is 197g mole^–1.

The volume of a given mass of a gas at 27°C, 1 atm is 100cc. What will be its volume at 327°C?

Explain why.
There is fall in temperature with increase in altitude.

A box of 1.00m3 is filled with nitrogen at 1.5 atm at 300K. The box has a hole of an area 0.010 mm2. How much time is required for the pressure to reduce by 0.10atm, if the pressure outside is 1atm.

Consider an ideal gas with following distribution of speeds.

Speed m/s	200	400	600	800	1000
% of molecules	10	20	40	20	10

If all the molecules with speed 1000m/s escape from the system, calculate new V_rms and hence T.

A gas mixture consists of molecules of A, B and C with masses m_A > m_B > m_c. Rank the three types of molecules in decreasing order of (a) average KE, (b) rms speeds.

Consider an ideal gas with following distribution of speeds.

Speed m/s	200	400	600	800	1000
% of molecules	10	20	40	20	10

Calculate V_rms and hence T. (m = 3.0 × 10^-26kg)