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EE 117A Spring 1996
Midterm II
Problem 1 of 4 (25 points)
What is Stoke^Òs theorem (in words or formulas)?
What is the divergence theorem ( in words or formulas)?
How much energy do you need to move one electron from the positive plateto the negative plate of a 10μ F capacitor thatis holding a charge of 0.001 Cb?
Below you are given the intensity of the electric field at one pointof a boundary, inside material "1". Sketch the F 2 at the other
side of the boundary. Both material are dielectrics
Sketch the forces (direction only, do not calculate size) exerted on thesquare loop by the infinitely long conductor. Sketch the direction of thetotal (net) force.
Problem 2 of 4 (25points)
a) Three point charges Q1=-9 (?C), Q2 (?C) and Q3 = -36 (?C)are arranged on a straight line. The distance between Q1 and Q is9 (cm). It is claimed that a location can be selected for Q2 suchthat each charge will experience a zero force. Find that location.
b) Find the energy needed to place the three charges at the locations specifiedin part (a). Assume that originally these three charges were at rest atinfinite distances from each other.
Problem 3 of 4 (25 points)
A circular insulating disk of radius a is charged with a uniform chargedensity of charge ρs (Cb/m^2 ).Find an expression for
electrostatic potential, V(z) and field intensityE(z) at a point P on the axis distance z from the disk
Assume a slab of charge having infinite transverse extent, a finitethickness d, and charge density ρo (Cb/m^3 ).Using Gauss^Ò
law, find the dependence of the potential difference acrossthe sheet on the thickness d.
Problem 4 of 4 (25 points)
