5.3 能源量化

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  能源量化

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  Every so often you hear a commercial or a news story with the words “ quantum leap” in it. The quantum leap is supposed to be a major breakthrough, a big change, something extraordinarily large. The reality is far different. Instead of the big, extravagant change, the “quantum” that scientists know about is a very small difference in the location of an around a nucleus – hardly an enormous shift at all.
  ::你经常听到一个商业或新闻故事,其中写着“量的飞跃 ” 。 量的飞跃应该是一个重大突破,一个巨大的变化,一个超大的东西。 现实大相径庭。 现实是完全不同的。 科学家所知道的“量的”不是巨大的大而奢侈的变化,而是核心周围位置的很小差异 — — 根本不是一个巨大的变化。

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  Quantization of Energy
  ::能源量化

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  German physicist Max Planck (1858-1947) studied the emission of light by hot objects. You have likely seen a heated metal object glow an orange-red color ( Figure ).
  ::德国物理学家马克斯·普朗克(18588-1947年)研究了热物体的光排放。你可能见过加热的金属物体发亮橙色(图)。

  

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  A heated object may glow different colors. The atoms in this piece of metal are releasing energy in discrete units called quanta.
  ::一种加热的物体可能发光不同颜色。这个金属块中的原子释放出一种叫做夸坦的离散单元的能量。

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  Classical physics, which explains the behavior of large, everyday objects, predicted that a hot object would emit electromagnetic energy in a continuous fashion. In other words, every wavelength of light could possibly be emitted. Instead, what Planck found by analyzing the spectra was that the energy of the hot body could only be lost in small discrete units. A quantum is the minimum quantity of energy that can either be lost or gained by an . An analogy is that a brick wall can only undergo a change in height by units of one or more bricks and not by any possible height. Planck showed that the amount of radiant energy absorbed or emitted by an object is directly proportional to the frequency of the radiation.
  ::解释大型日常物体行为的古老物理学预测,热物体会以连续的方式释放电磁能量。换句话说,每个波长的光都有可能被释放。相反,普朗克通过分析光谱发现,热体的能量只能消失在小离散单位中。量子是最小能量量,它可以丢失或从中获取。比方说,砖墙的高度只能由一个或多个砖块的单位改变,不能由任何可能的高度改变。普朗克显示,物体吸收或排放的光亮能量量与辐射频率直接成正比。

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  $$\begin{array}{r}E=hv\end{array}$$

  
  ::E=hv E=hv

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  In this equation,  $\begin{array}{r}E\end{array}$ is the energy, in joules, of a quantum of radiation,  $\begin{array}{r}v\end{array}$ is the frequency, and  $\begin{array}{r}h\end{array}$ is a fundamental constant called Planck’s constant . The value of Planck’s constant is $\begin{array}{r}h=6.626\times {10}^{-34}\text{J}\cdot \text{s}\end{array}$ . The energy of any system must increase or decrease in units of $\begin{array}{r}h\times v\end{array}$ . A small energy change results in the emission or absorption of low-frequency radiation, while a large energy change results in the emission or absorption of high-frequency radiation.
  ::在这个方程中,E是辐射量的能量,在焦耳中,是频率,h是普朗克的常数。Planck的常数值是h=6.626×10-34 J。任何系统的能量必须增加或减少hxv的单位。小能量变化导致低频辐射的排放或吸收,而大的能量变化则导致高频辐射的排放或吸收。

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  Sample Problem: Quantized Energy
  ::问题:量化能源

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  What is the energy of a photon of green light with a frequency of 5.75 × 10 ¹⁴ Hz?
  ::频率为5.75×1014赫兹的绿光光光光线光子的能量是什么?

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  Step 1: List the known quantities and plan the problem.
  ::第1步:列出已知数量并规划问题。

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  Known
  ::已知已知

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  • frequency  $\begin{array}{r}(\nu )\end{array}$ = 5.75 × 10 ¹⁴ Hz
    ::频率 = 5.75 × 1014赫兹
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  • Planck's constant  "> $\begin{array}{r}(h)\end{array}$ = 6.626 × 10 ^-34 J • s
    ::普朗克常数 = 6.626 × 10-34 J • s

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  Unknown
  ::未知

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  • energy  $\begin{array}{r}(E)\end{array}$
    :E) 能源(E)

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  Apply the equation $\begin{array}{r}E=hv\end{array}$ to solve for the energy.
  ::应用 E=hv 方程式解析能量 。

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  Step 2: Calculate.
  ::第2步:计算。

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  $\begin{array}{r}E=(6.626\times {10}^{-34}\text{J}\cdot \text{s})\times (5.75\times {10}^{14}\text{Hz})=3.81\times {10}^{-19}\text{J}\end{array}$
  ::E=( 6.626x10- 34 Js) ×( 5. 75x1014 Hz) = 3. 81x10-19 J

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  Step 3: Think about your result.
  ::步骤3:想想你的结果。

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  While the resulting energy may seem very small, this is for only one photon of light. Visible quantities of light consist of huge quantities of photons. Recall that a hertz is equal to a reciprocal second, so the units agree in the equation.
  ::虽然所产生的能量似乎很小,但这只用于一光子。 可见的光量是由大量光子构成的。 回想一下, 赫兹等于对等的二分之一, 所以单位在方程中同意 。

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  Summary
  ::摘要

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  • A quantum is the minimum quantity of energy that can either be lost or gained by an atom.
    ::量子是原子可能丢失或获得的最小能量量。
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  • The value of Planck’s constant is $\begin{array}{r}h=6.626\times {10}^{-34}\text{J}\cdot \text{s}\end{array}$ .
    ::Planck 的常数值为 h= 6. 626×10-34 Js。

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  Review
  ::回顾

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  1. What did classical physics predict about hot objects?
     ::古典物理学对热物体的预测是什么?
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  2. What did Planck find?
     ::普朗克发现了什么?
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  3. What is a quantum?
     ::什么是量子?