A polar molecule with a permanent dipole moment (of the order quoted for ammonia)…

PHYSICS · Subjective · Fermi University Physics · Thermal, Statistical & Complex Systems · Electricity, Magnetism & Electromagnetism · Electrostatic fields and potential

The Boundary-Value Problem, Ch Cylindrical geometry, edges, and what a field does to a dipole

Problem

A polar molecule with a permanent dipole moment

p = 5.0\times10^{-30}\,\mathrm{C\,m}

(of the order quoted for ammonia) sits in a field

E = 3.0\times10^6\,\mathrm{V\,m^{-1}}

(roughly the field near a sharp laboratory point electrode) at room temperature,

T = 300\,\mathrm{K}

. Estimate the ratio

pE/k_BT

, and say in one sentence what this ratio tells about how strongly the applied field aligns the molecule against thermal agitation.

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