The viscosity $\eta$ of a gas depends on the long-range attractive part of the intermolecular force, which varies with molecular separation $r$ according to $F \propto \mu r^{-n}$ where $n$ is a number and $\mu$ is a constant. If $\eta$ is a function of the mass $m$ of the molecules, their mean speed $v$, and the constant $\mu$, then which of the following is correct: