The Chocolate Crumb MysteryExplosions ignited by electrostatic discharges (sparks) constitute a serious danger infacilities handling grain or powder. Such an explosion occurred in chocolate crumbpowder at a biscuit factory in the 1970s. Workers usually emptied newly delivered sacksof the powder into a loading bin, from which it was blown through electrically groundedplastic pipes to a silo for storage. Somewhere along this route, two conditions for anexplosion were met:1. The magnitude of an electric field became 3.0 x 106 N/C or greater, so thatelectrical breakdown and thus sparking could occur.2. The energy of a spark was 150 mJ or greater so that it could ignite the powderexplosively.Let us check for the first condition in the powder flow through the plastic pipes.Suppose a stream of negatively charged powder was blown through a cylindrical pipe ofradius R = 5.0 cm. Assume that the powder and its charge were spread uniformlythrough the pipe with a volume charge density p.a. Using Gauss' law, find an expression for the magnitude of the electric field E inthe pipe as a function of radial distance r from the pipe center.b. Does E increase or decrease with increasing r?c. Is E directed radially inward or outward?d. For p = 1.1 x 103 C/m³ (a typical value at the factory), find the maximum E anddetermine where that maximum field occurs.e. Could sparking occur, and if so, where?

The link between surface charge density and electric field strength is used to find an expression…

a. Using Gauss' law, find an expression for the magnitude of the electric field E in the pipe as a function of radial distance r from the pipe center. b. Does E increase or decrease with increasing r? c. Is E directed radially inward or outward? d. For p = 1.1 x 10³ C/m³ (a typical value at the factory), find the maximum E and determine where that maximum field occurs. e. Could sparking occur, and if so, where?

a. Using Gauss' law, find an expression for the magnitude of the electric field E in the pipe as a function of radial distance r from the pipe center. b. Does E increase or decrease with increasing r? c. Is E directed radially inward or outward? d. For p = 1.1 x 10³ C/m³ (a typical value at the factory), find the maximum E and determine where that maximum field occurs. e. Could sparking occur, and if so, where?

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter25: Surge, Spike, And Lightning Protection

Section: Chapter Questions

Problem 10RQ: In reference to the load, how are capacitors connected to help prevent voltage spikes and surges?...

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