Emission and Absorption Spectra · 发射光谱与吸收光谱
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| spectrum/ˈspektrəm/ | 光谱 | guāng pǔ |
A barcode of light that names the element
- Split the light from a glowing gas and you don't get a rainbow — you get a few sharp coloured lines.
- The exact set of lines is different for every element — a barcode that names it.
- These spectra 光谱 come straight from the electron energy levels of the Bohr model.
- Astronomers read them to tell what distant stars are made of.
一种给元素命名的光之条形码
- 把发光气体的光分开,你得到的不是彩虹——而是几条尖锐的彩色线。
- 这组线的确切样子对每种元素都不同——一个给它命名的条形码。
- 这些光谱直接来自玻尔模型的电子能级。
- 天文学家读它们来判断遥远的恒星由什么构成。
Emission spectra
- Heat or excite a gas and its electrons jump up, then drop back down, emitting photons.
- Each drop emits one exact frequency, so you see bright lines on a black background.
- The emission spectrum is the set of frequencies that element gives off.
- Because the levels are unique, the line pattern is a fingerprint of the element.
发射光谱
- 加热或激发气体,它的电子向上跳,然后降回来,发出光子。
- 每次下降发出一个确切的频率,所以你看到黑色背景上的亮线。
- 发射光谱是那种元素发出的一组频率。
- 因为能级是独特的,这组线的样子是元素的指纹。
Lines from level jumps · 来自能级跃迁的谱线
Pick two levels and see the spectral line that a jump between them produces. · 选择两个能级，查看它们之间跃迁产生的谱线。
An emission spectrum shows: · 发射光谱显示：
Electrons dropping down emit photons, giving bright lines on black. · 电子向下跃迁时发射光子，在黑色背景上形成亮线。
Because each element has unique energy levels, its spectrum acts as a ____. · 因为每种元素都有独特的能级，其光谱充当了 ____。
The unique line pattern identifies the element like a fingerprint. · 独特的谱线模式像指纹一样识别该元素。
Absorption spectra
- Shine white light through a cool gas and the gas absorbs the frequencies its electrons can jump on.
- Those exact frequencies go missing, leaving dark lines in the otherwise continuous spectrum.
- The dark absorption lines fall at the same frequencies as that element's bright emission lines.
- So both spectra reveal the same fingerprint, one in light, one in shadow.
吸收光谱
- 让白光穿过冷气体,气体会吸收它的电子能跳上去的那些频率。
- 那些确切的频率就消失了,在原本连续的光谱中留下暗线。
- 暗的吸收线落在与那种元素亮发射线相同的频率处。
- 所以两种光谱揭示同一个指纹,一个在光中,一个在影中。
An absorption spectrum shows: · 吸收光谱显示：
The gas absorbs certain frequencies, leaving dark lines in the continuous spectrum. · 气体吸收特定频率，在连续光谱中留下暗线。
For a given element, its absorption lines fall at the same frequencies as its emission lines. · 对于给定元素，其吸收线位于与其发射线相同的频率处。
Both come from the same energy-level gaps, so they share the same frequencies. · 两者均源自相同的能级间隙，因此共享相同的频率。
Select all · 所有 true statements about spectra. · 选择关于光谱的所有正确陈述。
Emission = bright, absorption = dark, at the same frequencies. Each element's spectrum is unique. · 发射=亮线，吸收=暗线，且频率相同。每种元素的光谱都是独特的。
Reading the stars
- Sunlight has dark absorption lines from gases in the Sun's outer layers.
- Matching them to known elements tells us what the Sun (and other stars) contain.
- The element helium was discovered in the Sun's spectrum before it was found on Earth.
- Spectra turn a point of light into a full chemical analysis.
读懂恒星
- 阳光有来自太阳外层气体的暗吸收线。
- 把它们与已知元素匹配,就告诉我们太阳(和其他恒星)含有什么。
- 元素氦是先在太阳光谱中被发现,然后才在地球上找到的。
- 光谱把一个光点变成一份完整的化学分析。
Astronomers use spectral lines to identify the elements in distant stars. · 天文学家利用谱线来识别遥远恒星中的元素。
Matching a star's absorption lines to known elements reveals its composition. · 将恒星的吸收线与已知元素匹配可揭示其成分。
Emission and absorption lines for the same element sit at the same frequencies — one shows them bright (emitted), the other dark (absorbed). Don't treat them as unrelated: they are two views of the same set of energy-level gaps.
同一种元素的发射线和吸收线位于相同的频率处——一个把它们显示为亮(发射),另一个显示为暗(吸收)。别把它们当作无关:它们是同一组能级隙的两种视角。
An unknown gas glows with bright lines at exactly the frequencies of hydrogen's spectrum. What is the gas?
- The line pattern is hydrogen's unique fingerprint, so the gas is hydrogen.
- Cool hydrogen would show dark lines at those same frequencies in absorption.
一种未知气体发出的亮线恰好在氢光谱的频率处。这是什么气体?
- 这组线的样子是氢独特的指纹,所以气体是氢。
- 冷的氢会在那些相同频率处显示吸收的暗线。
Emission spectra show bright lines (electrons dropping down, emitting photons); absorption spectra show dark lines (electrons absorbing photons from white light). Both fall at the same frequencies — a unique fingerprint of the element. Astronomers use them to identify what stars are made of.
发射光谱显示亮线(电子向下降、发出光子);吸收光谱显示暗线(电子从白光中吸收光子)。两者落在相同的频率处——元素独特的指纹。天文学家用它们识别恒星的成分。