首页
登录
职称英语
From Dr. R. S. Scorer of Britain’s Imperial College of Science comes the la
From Dr. R. S. Scorer of Britain’s Imperial College of Science comes the la
游客
2024-10-31
12
管理
问题
From Dr. R. S. Scorer of Britain’s Imperial College of Science comes the latest theory about the cause of lightening flashes. Dr. Scorer believes the cause is hail falling through super - cooled clouds, lee particles bouncing off the falling hail acquire a positive charge and rise to the top of the cloud while the hail carries a negative charge to the bottom of the cloud.
According to Dr. Scorer, Benjamin Franklin first proved thunderclouds are charged with electricity. Later investigation showed that the tops of the clouds have a great positive charge and the bottoms a great negative charge.
When the charges become great enough to break down the insulating properties of the air, lightening flashes carry the electricity within the cloud, or from cloud to cloud, or from cloud to earth. But the question remained: how do the charges develop within the cloud?
To seek the cause, Dr. Scorer and his colleagues at the college first duplicated thundercloud currents in a liquid tank. They doubt that mixture takes place only in the tops of the clouds.
Next a study of thunderclouds over the North Atlantic showed that lightening occurs only when the air temperature around the cloud is below freezing. Particles at the top of the cloud begin to freeze, but those in the remainder of the cloud stay unfrozen although below freezing temperature.
To measure moisture, the scientists sent planes equipped with external refrigerated rods into the clouds. The idea was that moisture would freeze on the rods and could later be measured. The men found, however, that some of the moisture particles bounced off the rods. This accidental discovery set the scientists on a new course of action.
In the laboratory, S. E. Reynolds whirled a refrigerated rod through ice particles and found that the particles bounced off the rod acquired a positive charge. This was the missing link. Without hail and super-cooled clouds, he concluded there could be no lightening. [br] A study of thunderclouds over the North Atlantic showed that lightening occurred only when the air temperature ______.
选项
A、around the cloud was below freezing
B、above the cloud was lower than the temperature below the cloud
C、around the cloud was above freezing
D、of the cloud was above freezing
答案
A
解析
见原文第五段,“Next a study of thunder clouds over the North Atlantic showed that lightening occurs only when the air temperature around the cloud is below freezing”,因此A为正确选项。
转载请注明原文地址:https://tihaiku.com/zcyy/3825399.html
相关试题推荐
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
BlackdeaththatdroveNewtonfromhiscollegeandintoamomentousdiscove
随机试题
[originaltext]M:Lucyistakingsuchaheavyloadofclassesthissemester.Iw
简述工作分析的原则。
如图(彩图4)所示,该病例最可能的诊断是 A.主动脉窦瘤破裂 B.室间隔缺损
患者,女性,37岁。肛门周围瘙痒,肛周皮肤外口反复红肿,流脓,诊断为肛瘘。治疗的
2015年,我国规模以上电子信息产业企业个数6.08万家,其中电子信息制造企业1
所谓(),就是把儿童所应该学的东西结合在一起,完整地、系统地教授给儿童。A.吸收
非抗震设防的某钢筋混凝土板柱结构屋面层,某中柱节点如题图所示,构件安全等级为二级
下列物质中,食物的特殊动力作用最强的是A.糖 B.脂肪 C.蛋白质 D.维
患者,女,53岁。贫血病史10余年,全身检查其他未见异常。口内有残根,不松动,需
卡环需用对抗臂的主要目的是A.防止义齿移位 B.防止基牙移位 C.防止义齿摆
最新回复
(
0
)