0
$\begingroup$

In some cases we use (3/2)kt in some cases kt and some cases (1/2)kt. How to chose which formula to use for thermal energy?

$\endgroup$
2
$\begingroup$

Thermal energy is distributed evenly at the amount of $\frac 12 kT$ per degree of freedom of the dynamical system you're dealing with.

In particular, you very often use this to calculate the thermal energy held in the velocity of a particle in a gas, which comprises three independent degrees of freedom - the three components of the velocity. This multiplies the $\frac 12 kT$ by $3$ to give $\frac 32 kT$.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.