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107. एक गणित का उदाहरण इस ओर स्पष्ट करता है, देखें Text book of Physics (Std.
XII), part II, page 172— Probleml: Average surface charge density of the earth's surface is 10-9 coulomb/meter'. If there exists a potential difference of 400 volts between a certain layer of upper atmosphere above the earth's surface causing a current of 1800 amp (assumed constant) to flow from earth's surface to the atmosphere, how much time will it take earth's surface charge density to become zero? (Radius of Earth = 6400 km) Surface charge density 6 = 10% coulomb/meter Surface are of earth = 4 R : A = 51445.5 x 101° meter Total charge Q = QA = 10' x 51445.5 x 100 =5.144 x 10 coulomb. Q = It => t = - ९, = 5.144 x 10/1800 =0.2857 x 103 t = 285.7 second A Note: Thunderstorms continually going on at various places on the earth convey electrical charge to the surface of the earth maintaining
on an average conditions described in this problem.” 108. डॉ. जे. जैन, अप्रकाशित लेख, पृष्ठ 8-10 109. गुजरात समाचार, (दैनिक) अहमदाबाद, अर्ध साप्ताहिक पूर्ति शतदल, में 4-9-2002 को
डिस्कवरी कालम में प्रकाशित डॉ. विहारी छाया का लेख "आकाशनी बिजली पड़े त्यारे शरीर ने
केम हानि थाय"से उद्धत। 110. डॉ. जैन, पूर्व उद्धृत सन्दर्भ, पृष्ठ 27. 111. वही, पृ. 12 112. वही, पृ. 37 113. वही, पृ. 25 114. वही, पृ. 31
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तुलसी प्रज्ञा अंक 122
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