首页
登录
职称英语
Rubidium, potassium and carbon are three common elements used to date the his
Rubidium, potassium and carbon are three common elements used to date the his
游客
2025-04-16
11
管理
问题
Rubidium, potassium and carbon are three common elements used to date the history of Earth. The rates of radioactive decay of these elements are absolutely regular when averaged out over a period of time; nothing is known to change them. To be useful as clocks, the elements have to be fairly common in natural minerals, unstable but decay slowly over millions of years to form recognizable "daughter" products which are preserved minerals.
For example, an atom of radioactive rubidium decays to form an atom of strontium (another element) by converting a neutron in its nucleus to a proton and releasing an electron, generating energy in the process. The radiogenic daughter products of the decay-in this case strontium atoms--diffuse away and are lost above a certain very high temperature. So by measuring the exact proportions of rubidium and strontium atoms that are present in a mineral, researchers can work out how long it has been since the mineral cooled below that critical "blocking" temperature. The main problems with this dating method are the difficulty in finding minerals containing rubidium, the accuracy with which the proportions of rubidium and strontium are measured, and the fact that the method gives only the date when the mineral last cooled below the blocking temperature. Because the blocking temperature is very high, the method is used, mainly for recrystallized (igneous or metamorphic) rocks, not for sediments--rubidium-bearing minerals in sediments simply record the age of cooling of the rocks which were eroded to form the sediments, not the age of deposition of the sediments themselves.
Potassium decays to form (a gas) which is sometimes lost from its host mineral by escaping through pores. Although potassium-argon dating is therefore rather unreliable, it can sometimes be useful in dating sedimentary rocks because potassium is common in some minerals which form in sediments at low temperatures. Assuming no argon has escaped, the potassium-argon date records the age of the sediments themselves.
Carbon dating is mainly used in archaeology. Most carbon atoms (carbon-12) are stable and do not change over time. However, cosmic radiation bombarding the upper atmospheres constantly interacting with nitrogen in the atmosphere to create an unstable form of carbon, carbon-14. [br] What is the common feature of rubidium, potassium and carbon?
选项
A、They can be made into clocks.
B、They are rich in content.
C、Their decay is slow but regular.
D、The products of their decay are the same.
答案
C
解析
文章第1段指出rubidium、potassium和carbon这三种元素的rates of radioactive decay of these elements are absolutely regular,并且decay slowly over millions of years,故选项C正确。
转载请注明原文地址:https://tihaiku.com/zcyy/4040252.html
相关试题推荐
Pigeonisthecommonnameformembersofafamilyofbirds;smallerspeciesare
Businessisimprovingbutmuchmorehardworkandcommonsensewillbe______bef
Pigeonisthecommonnameformembersofafamilyofbirds;smallerspeciesare
Thereisanewtypeofsmalladvertisementbecomingincreasinglycommoninne
Thereisanewtypeofsmalladvertisementbecomingincreasinglycommoninne
Thereisanewtypeofsmalladvertisementbecomingincreasinglycommoninne
Thereisanewtypeofsmalladvertisementbecomingincreasinglycommoninne
Researchiscommonlydividedinto"applied"and"pure".Thisclassificationi
Researchiscommonlydividedinto"applied"and"pure".Thisclassificationi
Theseisanewtypeofadvertisementbecomingincreasinglycommoninnewspape
随机试题
Withsomanycompanies______backontheirworkforcelately,doyouknowhowan
NewDiscoveriesofPublicTransportA)Anewstudyconductedfor
若在进行渗水试验之前,并未对行车道路面进行清扫,则()。A.会影响最终渗水系数
2岁男孩,发热、咳嗽4天入院,经抗感染治疗2天,咳嗽加重,非犬吠样,神志萎靡,不
下列行为中违反《中国人民银行法》的有()。 ①发行人未经中国人民银行核准擅
财政政策实现资源的优化配置的核心问题是:A、收支平衡 B、充分就业 C、价格
左边给定的是纸盒的外表面,下列哪一项能由它折叠而成? A.如上图所示 B.如
某商店贴出下列四个标语,不合法的是()。 ①特价商品,概不退还 ②商
一名癫痫大发作的患者,因服用过量的苯巴比妥而引起昏迷,呼吸微弱,送医院急救。不该
关于速发性哮喘反应,不正确的是A.6小时左右发病 B.平滑肌收缩 C.B细胞
最新回复
(
0
)