Dr. Hugh Blanton ENTC 3331

Charge Distributions

Dr. Blanton - ENTC Charge Distribution 3 Electron Negative charge Greek for amber Discovered in 1897 by J.J. Thompson Elementary charge—1.6  C.

Dr. Blanton - ENTC Charge Distribution 4 Volume charge density: In general volume charge density is defined at a given point in space.

Dr. Blanton - ENTC Charge Distribution 5 Rewriting the equation for volume charge density yields: Thus the total charge of Q in volume, V, is:

Dr. Blanton - ENTC Charge Distribution 6 What is the total charge Q for a spherical shell 2cm  R  3cm with a charge distribution of x z y

Dr. Blanton - ENTC Charge Distribution 7 (important: convert units cm  m before integration) spherical coordinates

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Dr. Blanton - ENTC Charge Distribution 12 Repulsion of charges and mobility in a conductor often depend upon surface charge

Dr. Blanton - ENTC Charge Distribution 13 Surface charge density is: Thus the total charge of Q in volume, V, is:

Dr. Blanton - ENTC Charge Distribution 14 Suppose you have a disk with a surface charge of: What is the total surface charge?

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Dr. Blanton - ENTC Charge Distribution 16 Find the surface area of the section shown. Using the spherical coordinate system,

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Dr. Blanton - ENTC Charge Distribution 18 Line Charge Density Thin wire cm

Dr. Blanton - ENTC Charge Distribution 19 What is the total charge, if the line density is: cm

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Dr. Blanton - ENTC Charge Distribution 21 What is the total charge on the square plate?

Dr. Blanton - ENTC Charge Distribution 22 Find the total charge for the disk. a Hint:

Dr. Blanton - ENTC Charge Distribution 23 Find the total charge for the cube. 2 m x z y