“lightning”的概念、定义、习题解题方法及翻译-物理辞典

单词	lightning
释义	lightning A high-energy luminous electrical discharge that passes between a charged cloud and a point on the surface of the earth, between two charged clouds, or between oppositely charged layers of the same cloud. In general, the upper parts of clouds are positively charged and the lower parts are negatively charged; the reasons for this separation of charge are complex. Lightning usually occurs in the form of a downward step leader followed by an intensely luminous return stroke, which can produce instantaneous temperatures as high as 30 000°C. In the typical step leader a surge of electrons descends in approximately 50-metre steps with about 50-microsecond pauses between steps. When this leader reaches the earth a surge of charge returns up the preionized path taken by the leader. Cloud-to-cloud strokes also involve a leader and return stroke. The average current in a lightning stroke is about 10 000 amperes, but maximum currents in the return stroke can reach 20 000 A. See also ball lightning
随便看	astigmatism Aston, Francis William astrometry astronomical telescope astronomical unit astronomy astrophysics asymmetric atom asymptote asymptotic freedom asymptotic series atmolysis atmosphere atmospheric pressure atom atomic bomb atomic clock atomic energy atomic force microscope atomic mass unit atomic number atomic orbital atomic pile atomic volume atomic weight

物理辞典收录了3346条物理词条，基本涵盖了常用物理知识及物理英语单词词组的翻译及用法，是物理学习的有利工具。