Class 11 Physics Kinetic Theory | Vibrational degree of freedom |
Vibrational degree of freedom
one-dimensional oscillator.
(1/2) m(dy/dt)^{2}=Kinetic energy and (1/2)ky^{2} =Potential energy and k=force constant one-dimensional oscillator.
(1)
(2)
(1) Rotational motion along two axis perpendicular to line joining two particles (here y and z directions)
(2) Vibrational motion along line joining the two atoms
Comparison between 3 energy modes
Translational |
Rotational |
Vibrational |
E_{t}=(1/2)mv_{x}^{2} |
E_{r}=(1/2)I ω^{2} |
E_{v} = (1/2)m (dy/dt)^{2}+(1/2)ky^{2} |
1 squared term is being contributed |
1 squared term is being contributed |
2 squared term is being contributed |
Law of Equipartition of energy
According to this law, in equilibrium, the total energy is equally distributed in all possible energy modes, with each mode having an average energy equal to (1/2)k_{B}T.
.