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
2018-04-17
29
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/9OiC777K
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
Inthisexperiment,theyarewokenupseveraltimesduringthenight,andaskedtoreportwhatthey______.
Pickouttheappropriateexpressionsfromtheeightchoicesbelowandcompletethefollowingdialogsbyblackeningthecorrespon
Whenallthepeoplehadassembled,theking,surroundedbyhiscourt,【C1】______asignal.Thenadoorbeneathhimopened,andt
Whenallthepeoplehadassembled,theking,surroundedbyhiscourt,【C1】______asignal.Thenadoorbeneathhimopened,andt
ItwasAnn’sfirstexperienceofflying.Shehadalwaysbeenafraidofheightsandsowaspreparedtobefrightened.Onlythe
It’sinterestinghowlittlemostofUSknowaboutourancestorsoraboutthehistoryofourfamily.Ifyou【56】tobenobility(贵族
Myfriend,EmmaDanicls,spentthesummerof1974travelinginIsrael.Duringhermonth-longstayinJerusalem,sheoftenwentt
Doyoufindgettingupinthemorningsodifficultthatit’spainful?Thismightbecalledlaziness,butDr.Kleitmanhasanew
TheCaliforniacondoristhelargestbirdinNorthAmerica.Itisanendangeredspecies.20yearsagotherewerelessthan30bi
Longtimeago,theancientpeoplecouldnottraveltoanyfarawayplacesfortheyhadnoinstrumentstocarrythemacrossthewi
随机试题
程序控制类指令的功能是()。
有关结膜浆细胞瘤的叙述,错误的是
用于去甲肾上腺素静脉滴注外漏时用于控制甲状腺功能亢进症状
主动红外探测器的特点是()。
下列情况中,会发生垄断性收入的有()。
备课要做好三方面的工作:一是钻研教材;二是了解学生;三是设计教法。()
Helearnsinaschool.Hepreparesmealsintherestaurant.
CampaigningontheIndianfrontierisanexperiencebyitself.Neitherthelandscapenorthepeoplefindtheircounterpartsina
象征
Thehorseandcarriageisathingofpast,butloveandmarriageaxestillwithusandstillcloselyinterrelated.MostAmerica
最新回复
(
0
)