首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
专升本
The accuracy of scientific observations and calculations is always at the mercy of the scientist’s time-keeping methods. For thi
The accuracy of scientific observations and calculations is always at the mercy of the scientist’s time-keeping methods. For thi
admin
2017-09-04
38
问题
The accuracy of scientific observations and calculations is always at the mercy of the scientist’s time-keeping methods. For this reason, scientists are interested in devices that give promise of more precise time-keeping.
In their search for precision, scientists have turned to atomic clocks that depend on various vibrating atoms or molecules to supply their "ticking". This is possible because each kind of atom or molecule has its own characteristic rate of vibration. Atom in ammonia, for example, vibrates or "ticks" 24 billion times a second.
One such atomic clock is so accurate that it will probably lose no more than a second in 3000 years. It will be of great importance in fields such as astronomical observation and long-range navigation. The heart of this Atomichron is a cesium (铯) atom that vibrates 9. 2 billion times a second when heated to the temperature of boiling water.
An atomic clock that operates with an ammonia molecule may be used to check the accuracy of predictions based on Einstein’s relativity theories, according to which a clock in motion and a clock at rest should keep time differently. Placed in an orbiting satellite moving at a speed of 18,000 miles an hour, the clock could broadcast its time readings on a similar model. Whatever differences develop would be checked against the differences predicted.
From the selection, we may assume that temperature changes________.
选项
A、affect only ammonia molecules
B、may affect the vibration rate of atoms
C、affect the speed at which atoms travel
D、do not affect atoms in any way
答案
B
解析
由文章第三段The heart of this Atomichron is a cesium(铯)atom that vibrates 9.2 billion times a second when heated to the temperature of boiling water.可知温度(temperature)会影响cesium铯原子的震动次数。所以选B。
转载请注明原文地址:https://kaotiyun.com/show/JiiC777K
本试题收录于:
英语题库成考专升本分类
0
英语
成考专升本
相关试题推荐
Pickouttheappropriateexpressionsfromtheeightchoicesbelowandcompletethefollowingdialoguesbyblackeningthecorresp
Pickouttheappropriateexpressionsfromtheeightchoicesbelowandcompletethefollowingdialoguesbyblackeningthecorresp
Pickouttheappropriateexpressionsfromtheeightchoicesbelowandcompetethefollowingdialoguesbyblackeningthecorrespo
Pickouttheappropriateexpressionsfromtheeightchoicesbelowandcompetethefollowingdialoguesbyblackeningthecorrespo
Pickouttheappropriateexpressionsfromtheeightchoicesbelowandcompetethefollowingdialoguesbyblackeningthecorrespo
Ialwayshaveadifficulttimechoosingoriginalbirthdaypresents.Myimaginationneverseemstogetbeyondties,handkerchiefs
When______behind,thelittlegirlalwayscriesforMum.
ItwasAnn’sfirstexperienceofflying.Shehadalwaysbeenafraidofheightsandsowaspreparedtobefrightened.Onlythe
ItwasAnn’sfirstexperienceofflying.Shehadalwaysbeenafraidofheightsandsowaspreparedtobefrightened.Onlythe
Afterscientistsdidsomeresearch______thehealthofworkers,thegovernmenttriedtofindsomewaytomeettheirdemand.
随机试题
下列各项不属于金融期货交易制度的是()。
______,theprofessorisstilltryingtolearnanewlanguage.
骨折急救处理中哪项不恰当()
中央型肺癌最早出现的征象是( )
李大伟是M城市商业银行的董事,其妻张霞为S公司的总经理,其子李小武为L公司的董事长。2009年9月,L公司向M银行的下属分行申请贷款1000万元。其间,李大伟对分行负责人谢二宝施加压力,令其按低于同类贷款的优惠利息发放此笔贷款。L公司提供了由保证人陈富提供
根据城市经济学原理,调控城市规模的最好手段是()
计算机处于工作状态下的重新启动称为加电启动。 ( )
Internet上许多复杂网络和不同类型计算机之间能够互相通信的基础是()。
增值税的优点有()。
对下列句子中加下划线字的意义和用法判断正确的是()。①其真无马邪?其真不知马也②今存其本,不忍废③若所市于人者④若为佣耕,何富贵也
最新回复
(
0
)