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Physics · 术语表

什么是 Incandescent sources?

又称: incandescence

Definition 11.12 High School Physics · 第 11 章 — Color and Light Sources

A source glowing because it is hot — flame, filament, star — shines by incandescence. Its spectrum is the continuous thermal spectrum of Chapter 2, and its peak obeys Wien’s law (Proposition 2.7),

λmax⁡×T=2.90×10−3 m K,\lambda_{\max} \times T = 2.90 \times 10^{-3}\,\mathrm{m}\,\mathrm{K},

our quantitative tool from now on: peak measured, temperature known.

Thermal spectra at 6000\, K and 3000\, K, peaks _ dashed at 483 and 967\, nm; the cooler curve, magnified twelve times, would otherwise hug the axis.
Thermal spectra at 6000 K6000\,\mathrm{K} and 3000 K3000\,\mathrm{K}, peaks λmax⁡\lambda_{\max} dashed at 483483 and 967 nm967\,\mathrm{nm}; the cooler curve, magnified twelve times, would otherwise hug the axis.

示例

Example 11.13 (A very inefficient lamp)

A tungsten filament at T=2700 KT = 2700\,\mathrm{K} peaks at λmax⁡=2.90×10−3 m K/2700 K=1.07×10−6 m=1070 nm\lambda_{\max} = 2.90 \times 10^{-3}\,\mathrm{m}\,\mathrm{K}/2700\,\mathrm{K} = 1.07 \times 10^{-6}\,\mathrm{m} = 1070\,\mathrm{nm}, deep in the infrared: most of the electric power leaves as invisible radiation, only about 5%5\% as light — the incandescent bulb was mainly a heater.

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