Diatomic molecules like hydrogen haven energy due to both translational as well as rotational motion. From the equation in kinetic theory `PV=(2)/(3)E,E` is

Options

A. The total energy per unit volume
B. Only the translational part of energy because rotational energy is very small compared to translational part of energy because rotational energy is very small compared to translational energy
C. Only the translational part of the energy because during collisions with the wall pressure relates changes in linear momentum
D. The trnaslational part of the energy because roatational enegies of molecules can be of either sign and its average over all the molecules is zero

Answer

C

Explanation

Sol, (c) According to Kinetic theory equation, `PV=(2)/(3)E ["where P = pressure V=volume"]`
E is representing only translational part of energy. Internal energy contains all types of energies like translation, rotational, vibrational etc. But the molecules of an ideal gas is treated as point masses in kinetic theory, so its kinetic energy is only due to translational motion. point mass does not have rotational or vibrational motion. Here we assumed that the walls only exert perpendiucalr forces on molecules. They do not exert any parallel force, hence there will not be any tuype of rotation present. The wall produces only charges in translational motion.