AM radio can be sent over larger distances, but the quality of the sound is not as good as a later kind of radio signal processing, called frequency modulation.

VOA: special.2010.12.08

So, this really just means for frequency, it's a frequency label.

你要说米每秒，所以它仅仅是，用来表示频率的，是个频率的标志。

麻省理工公开课 - 化学原理课程节选

It says, "This is such and such a frequency."

数据表明,这光是多少多少频率的

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So, if something cycles through five wavelengths in a single second, we would just say that the frequency of that wave is five per second.

如果一个东西在一秒,内经历了五个波长，我们就说这个波的,频率是每秒5次。

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We would specify a precise frequency here another one up here but what that gentleman was singing was all the stuff in between.

我们指定一个特定的频率,标记在这里,另一个频率标记在这里,但刚才那位先生唱的,都在音符之间游走

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The diet diary--the food frequency is a different kind of questionnaire.

饮食日记,食用频率,是另一种问卷调查方式

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The World Health Organization keeps track of what countries have cases of polio and when they occur, and what the frequency of--So, this is a map from a few years ago and there are efforts that occur occasionally.

世界卫生组织一直跟踪记录,发生小儿麻痹症的国家及发病时间,以及发生的频率,那么,这是从几年前开始统计的,一个地图,这里是一些偶然产生的成就

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If we have a high frequency, what about the wavelength, long or short? All right. Good. So we should always be able to keep these relationships in mind.

如果频率高，那波长是长还是短？,好，不错，我们要记住这些关系,类似的。

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So, similarly in a case where instead we have a small energy difference, we're going to have a low frequency, which means that we're going to have a long wavelength here.

在这个例子里,能量差较小,我们得到的频率低,这意味这它的波长更长。

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So, for example, we were talking about a threshold frequency as in a minimum frequency of light that you need in order to eject an electron from a metal surface.

举个例子来说，我们谈论的临界频率是,光从金属表面逐出一个电子,所需的最小频率。

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It has to do with frequency ratios that we'll go in to a little bit next time.

它和频率比有关,下次我们再详细介绍

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So that's the important take-away message from this slide. If we think about these different types of lights, microwave light, if it's absorbed by a molecule, is a sufficient amount of frequency and energy to get those molecules to rotate. That, of course, generates heat, so that's how your microwaves work.

重要的信息，如果我们看看,这些不同种类的光，微波,如果被分子吸收，它的频率和能量可以,使分子转动,这当然的，会产生热量,这就是你们微波炉的工作原理。

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So these are symbols telling us how long a particular frequency is to endure.

因此,这些符号是告诉我们,某个特定的声音频率要持续多长时间

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A food frequency--by the way, you also have the issue of whether the particular twenty-four hours that a person is interviewed is representative of their diet overall, because you can imagine how much your food intake varies from day to day.

食物摄取频率,顺便说下,还有一个问题,就是在选取的24小时里,测试者,是不是对总体有代表性,因为你可以想象,每天事物的摄入量都是不同的

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Any frequency can't have an energy, you have to -- you don't have a continuum of frequencies that are of a certain energy, it's actually punctuated into these packets that are called photons.

任何频率不能有个能量,你必须要-对某一个能量上,你不会有连续的频率,光子实际上分立的存在。

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