-理工类相同项单选集考试卷模拟考试题_0

1、姓名：_ 班级：_ 学号：_-密-封 -线- *理工类相同项单选集考试卷模拟考试题考试时间：120分钟 考试总分：100分题号一二三四五总分分数遵守考场纪律，维护知识尊严，杜绝违纪行为，确保考试结果公正。1、radiocarbon datingnowadays scientists can answer many questions about the past through a technique called radiocarbon (放射), or carbon-14, dating. one key to understanding how and why something hap

2、pened is to discover when it happened.radiocarbon dating was developed in the late 1940s by physicist willard f. libby at the university of chicago. an atom of ordinary carbon, called carbon-12, has six protons (质子) and six neutrons (中子) in its nucleus(原子核). carbon-14,or c-14,is a radioactive,unstab

3、le form of carbon that has two extra neutrons. it returns to a more stable form of carbon through a process called decay(衰减). this process involves the loss of the extra neutrons and energy from the nucleus.in libbys radiocarbon dating technique, the weak radioactive emissions (放射)from this decay pr

4、ocess are counted by instruments such as a radiation detector and counter. the decay rate is used to determine the proportion of c-14 atoms in the sample being dated.carbon-14 is produced in the earths atmosphere when nitrogen(氮)-14,or n-14,interacts with cosmie rays(宇宙射线). scientists believe since

5、the earth was formed, the amount of nitrogen in the atmosphere has remained constant. consequently,c-14 formation is thought to occur at a constant rate. now the ratio of c-14 to other carbon atoms in the atmosphere is known. most scientists agree that this ratio is useful for dating items back to a

6、t least 50,000 years.all life on earth is made of organic molecules(分子)that contain carbon atoms coming from the atraosphere. so all living things have about the same ratio of c-14 atoms to other carbon atoms in their tissues(组织). once an organism(有机体)dies it stops taking in carbon in any form, and

7、the c-14 already ,resent begins to decay. over time the amount of c-14 in the material decreases, and the ratio of c-14 to other carbon atoms goes down. in terms of radiocarbon dating,the fewer c-14 atoms in a sample,the older that sample is.nowadays many scientists depend on radiocarbon for dating

8、age-old objects.（ ）a.rightb.wrongc.not mentioned2、radiocarbon datingnowadays scientists can answer many questions about the past through a technique called radiocarbon (放射), or carbon-14, dating. one key to understanding how and why something happened is to discover when it happened.radiocarbon dati

9、ng was developed in the late 1940s by physicist willard f. libby at the university of chicago. an atom of ordinary carbon, called carbon-12, has six protons (质子) and six neutrons (中子) in its nucleus(原子核). carbon-14,or c-14,is a radioactive,unstable form of carbon that has two extra neutrons. it retu

10、rns to a more stable form of carbon through a process called decay(衰减). this process involves the loss of the extra neutrons and energy from the nucleus.in libbys radiocarbon dating technique, the weak radioactive emissions (放射)from this decay process are counted by instruments such as a radiation d

11、etector and counter. the decay rate is used to determine the proportion of c-14 atoms in the sample being dated.carbon-14 is produced in the earths atmosphere when nitrogen(氮)-14,or n-14,interacts with cosmie rays(宇宙射线). scientists believe since the earth was formed, the amount of nitrogen in the at

12、mosphere has remained constant. consequently,c-14 formation is thought to occur at a constant rate. now the ratio of c-14 to other carbon atoms in the atmosphere is known. most scientists agree that this ratio is useful for dating items back to at least 50,000 years.all life on earth is made of orga

13、nic molecules(分子)that contain carbon atoms coming from the atraosphere. so all living things have about the same ratio of c-14 atoms to other carbon atoms in their tissues(组织). once an organism(有机体)dies it stops taking in carbon in any form, and the c-14 already ,resent begins to decay. over time th

14、e amount of c-14 in the material decreases, and thl3、radiocarbon datingnowadays scientists can answer many questions about the past through a technique called radiocarbon (放射), or carbon-14, dating. one key to understanding how and why something happened is to discover when it happened.radiocarbon d

15、ating was developed in the late 1940s by physicist willard f. libby at the university of chicago. an atom of ordinary carbon, called carbon-12, has six protons (质子) and six neutrons (中子) in its nucleus(原子核). carbon-14,or c-14,is a radioactive,unstable form of carbon that has two extra neutrons. it r

16、eturns to a more stable form of carbon through a process called decay(衰减). this process involves the loss of the extra neutrons and energy from the nucleus.in libbys radiocarbon dating technique, the weak radioactive emissions (放射)from this decay process are counted by instruments such as a radiatio

17、n detector and counter. the decay rate is used to determine the proportion of c-14 atoms in the sample being dated.carbon-14 is produced in the earths atmosphere when nitrogen(氮)-14,or n-14,interacts with cosmie rays(宇宙射线). scientists believe since the earth was formed, the amount of nitrogen in the

18、 atmosphere has remained constant. consequently,c-14 formation is thought to occur at a constant rate. now the ratio of c-14 to other carbon atoms in the atmosphere is known. most scientists agree that this ratio is useful for dating items back to at least 50,000 years.all life on earth is made of o

19、rganic molecules(分子)that contain carbon atoms coming from the atraosphere. so all living things have about the same ratio of c-14 atoms to other carbon atoms in their tissues(组织). once an organism(有机体)dies it stops taking in carbon in any form, and the c-14 already ,resent begins to decay. over time

20、 the amount of c-14 in the material decreases, and the ratio of c-14 to other carbon atoms goes down. in terms of radiocarbon dating,the fewer c-14 atoms in a sample,the older that sample is.an atom of ordinary carbon has six protons and eight neutrons.（ ）a.rightb.wrongc.not mentioned4、radiocarbon d

21、atingnowadays scientists can answer many questions about the past through a technique called radiocarbon (放射), or carbon-14, dating. one key to understanding how and why something happened is to discover when it happened.radiocarbon dating was developed in the late 1940s by physicist willard f. libb

22、y at the university of chicago. an atom of ordinary carbon, called carbon-12, has six protons (质子) and six neutrons (中子) in its nucleus(原子核). carbon-14,or c-14,is a radioactive,unstable form of carbon that has two extra neutrons. it returns to a more stable form of carbon through a process called de

23、cay(衰减). this process involves the loss of the extra neutrons and energy from the nucleus.in libbys radiocarbon dating technique, the weak radioactive emissions (放射)from this decay process are counted by instruments such as a radiation detector and counter. the decay rate is used to determine the pr

24、oportion of c-14 atoms in the sample being dated.carbon-14 is produced in the earths atmosphere when nitrogen(氮)-14,or n-14,interacts with cosmie rays(宇宙射线). scientists believe since the earth was formed, the amount of nitrogen in the atmosphere has remained constant. consequently,c-14 formation is

25、thought to occur at a constant rate. now the ratio of c-14 to other carbon atoms in the atmosphere is known. most scientists agree that this ratio is useful for dating items back to at least 50,000 years.all life on earth is made of organic molecules(分子)that contain carbon atoms coming from the atra

26、osphere. so all living things have about the same ratio of c-14 atoms to other carbon atoms in their tissues(组织). once an organism(有机体)dies it stops taking in carbon in any form, and the c-14 already ,resent begins to decay. over time the amount of c-14 in the material decreases, and the ratio of c-

27、14 to other carbon atoms goes down. in terms of radiocarbon dating,the fewer c-14 atoms in a sample,the older that sample is.radar is used to determine the characteristics of radiocarbon.（ ）a.rightb.wrongc.not mentioned5、radiocarbon datingnowadays scientists can answer many questions about the past

28、through a technique called radiocarbon (放射), or carbon-14, dating. one key to understanding how and why something happened is to discover when it happened.radiocarbon dating was developed in the late 1940s by physicist willard f. libby at the university of chicago. an atom of ordinary carbon, called

29、 carbon-12, has six protons (质子) and six neutrons (中子) in its nucleus(原子核). carbon-14,or c-14,is a radioactive,unstable form of carbon that has two extra neutrons. it returns to a more stable form of carbon through a process called decay(衰减). this process involves the loss of the extra neutrons and

30、energy from the nucleus.in libbys radiocarbon dating technique, the weak radioactive emissions (放射)from this decay process are counted by instruments such as a radiation detector and counter. the decay rate is used to determine the proportion of c-14 atoms in the sample being dated.carbon-14 is prod

31、uced in the earths atmosphere when nitrogen(氮)-14,or n-14,interacts with cosmie rays(宇宙射线). scientists believe since the earth was formed, the amount of nitrogen in the atmosphere has remained constant. consequently,c-14 formation is thought to occur at a constant rate. now the ratio of c-14 to othe

32、r carbon atoms in the atmosphere is known. most scientists agree that this ratio is useful for dating items back to at least 50,000 years.all life on earth is made of organic molecules(分子)that contain carbon atoms coming from the atraosphere. so all living things have about the same ratio of c-14 at

33、oms to other carbon atoms in their tissues(组织). once an organism(有机体)dies it stops taking in carbon in any form, and the c-14 already ,resent begins to decay. over time the amount of c-14 in the material decreases, and the ratio of c-14 to other carbon atoms goes down. in terms of radiocarbon dating

34、,the fewer c-14 atoms in a sample,the older that sample is.radiocarbon is reliable in dating an object back to at least 50,000 years.（ ）a.rightb.wrongc.not mentioned6、radiocarbon datingnowadays scientists can answer many questions about the past through a technique called radiocarbon (放射), or carbon

35、-14, dating. one key to understanding how and why something happened is to discover when it happened.radiocarbon dating was developed in the late 1940s by physicist willard f. libby at the university of chicago. an atom of ordinary carbon, called carbon-12, has six protons (质子) and six neutrons (中子)

36、 in its nucleus(原子核). carbon-14,or c-14,is a radioactive,unstable form of carbon that has two extra neutrons. it returns to a more stable form of carbon through a process called decay(衰减). this process involves the loss of the extra neutrons and energy from the nucleus.in libbys radiocarbon dating t

37、echnique, the weak radioactive emissions (放射)from this decay process are counted by instruments such as a radiation detector and counter. the decay rate is used to determine the proportion of c-14 atoms in the sample being dated.carbon-14 is produced in the earths atmosphere when nitrogen(氮)-14,or n

38、-14,interacts with cosmie rays(宇宙射线). scientists believe since the earth was formed, the amount of nitrogen in the atmosphere has remained constant. consequently,c-14 formation is thought to occur at a constant rate. now the ratio of c-14 to other carbon atoms in the atmosphere is known. most scient

39、ists agree that this ratio is useful for dating items back to at least 50,000 years.all life on earth is made of organic molecules(分子)that contain carbon atoms coming from the atraosphere. so all living things have about the same ratio of c-14 atoms to other carbon atoms in their tissues(组织). once a

40、n organism(有机体)dies it stops taking in carbon in any form, and the c-14 already ,resent begins to decay. over time the amount of c-14 in the material decreases, and the ratio of c-14 to other carbon atoms goes down. in terms of radiocarbon dating,the fewer c-14 atoms in a sample,the older that sampl

41、e is.when an organism dies,the c-14 in it begins to decay.（ ）a.rightb.wrongc.not mentioned7、radiocarbon datingnowadays scientists can answer many questions about the past through a technique called radiocarbon (放射), or carbon-14, dating. one key to understanding how and why something happened is to

42、discover when it happened.radiocarbon dating was developed in the late 1940s by physicist willard f. libby at the university of chicago. an atom of ordinary carbon, called carbon-12, has six protons (质子) and six neutrons (中子) in its nucleus(原子核). carbon-14,or c-14,is a radioactive,unstable form of carbon that has two extra neutrons. it returns to a more stable form of carbon through a process called decay