CND-22

Dulong–Petit law

C = 3 n R. Classical high-temperature heat capacity of a solid.

Reading speed

PhononsDulong–Petit

Governing equation

C=3nR

where

n: Amount (mol)
C: Heat capacity (J/K)

Lecture brief

Historical brief

Drude electrons, Bloch waves, BCS pairing (1957) and Wiedemann–Franz heat are the first solids-and-metals laws. The lab is conductivity, gap and phonon heat in closed form. This sheet (CND-22 — Dulong–Petit law) is the form associated with Dulong–Petit. Working symbols: $n$ $\rightarrow$ $C$ . Equipartition: 3 oscillators per atom, ½ kT kinetic + ½ kT potential each.

Purpose

Purpose: compute

C

from

n

in Condensed matter via

C=3nR

C = 3 n R. Classical high-temperature heat capacity of a solid. Use it when a real condensed matter question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

n = 1.000\,\mathrm{mol}

, the governing relation

C=3nR

yields

C = 24.94\,\mathrm{J/K}

. A saturating C bar at 3R. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Amount n1 mol

Outputs

Heat capacity C24.94 J/K

Reading speed

Watch on YouTube

Free library

Full library

Free PDF / open book

YouTube channels

00:0 / 00:08

Narration of this film

A saturating C bar at 3R.

Equipartition: 3 oscillators per atom, ½ kT kinetic + ½ kT potential each.

Reading speed

Watch on YouTube