Well, we can't guarantee with UV light we'll have enough energy to eject every single electron, so that's why when we use x-rays, they're higher energy, you can pretty much be guaranteed we're going to eject all of those electrons there.
好,我们不能保证紫外光有足够的能量,激发出每一个电子,所以我们要使用,X,射线,它的能量更高,你可以非常确定,我们可以激发出其中所有的电子。
But for now let's simply say that we have a diffraction which we know occurs only by wave-like behavior and it involves the use of x-rays. Why x-rays?
但现在让我们来简单假设一下,我们知道,只波才发生衍射,而且衍射涉及了X光的使用,为什么是X光?
So the way that we really make sure this is done is that we use x-rays.
我们保证能做到这一点的方法是,使用,X,射线。
How do I posit-- why do I believe in x-rays, even though I don't see them?
我如何证实,我为什么会相信X射线是存在的,尽管我压根看不见它
Funny story, I met him because at MIT they signed us all up for chest x-rays alphabetically-- that's the way MIT does things, an orderly way.
有趣的是,我在MIT遇到他是因为,我们按姓氏字母顺序,排队去照胸透,MIT做事总是用这种有条理的方式
There is no way that you could irradiate a crystal of nickel with a single beam of x-rays and get that circular ring pattern if the electron beam were behaving as a particle beam only.
没有什么其他的途径,可以让镍晶体发射,单束X光来,继而得到环状图案,如果电子束,是以粒子束形式出现的。
People have been working with x-rays for about 30 years by this time.
到现在为止,人类和X射线打交道大约30年了。
Here it is showing x-rays. He used x-rays.
这展示的是X射线,他使用X射线。
If de Broglie is correct, let's irradiate the nickel crystal with a beam of electrons where the wavelength of the beam of electrons is identical to the wavelength of the x-rays that were used and see what we get.
如果德·布罗意是正确的,那么镍晶体放出,电子光束,电子束的波长,和原来讲过的X光的波长是相等的,再看看得到了什么。
So you know that x-rays are higher frequency than UV light, for example, that means it's also higher energy than UV light, and if you think back to our photoelectric effect experiments, do you remember what type of light we were usually using for those? Does anyone remember?
你们知道,X,射线的频率比紫外光高,这意味着,它的能量也比紫外光要高,那么,请大家回想一下我们的光电效应实验,大家还记得当时我们用的是什么光源吗?,有人记得吗?
This is h nu. X-rays coming in.
这是hv,X光出现了。
They took a crystal, this is a single crystal of nickel that has regular planes of atoms, and those planes are spaced on the order of an angstrom or less apart, and they irradiated this with x-rays.
他们取了个晶体,一个具有规则原子平面的,镍晶体,这些面间距差不多也是一埃或者更少,它们放射出X射线。
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