ECE 107
Midterm
Thursday, February 5, 2015
Name: _
Please show all your work for more rational grading.
Try to give solutions as formulas, i.e. symbolically, and then, substitute numbers to give your
final answers if needed. Indicate units in numerical an

ECE 107
QUIZ 2
Monday, February 24, 2014
Name: _
Please show all your work for more rational grading.
Box your answers.
GRADING:
1) 34 points _
2) 33 points _
3) 33 points _
Total (100 points) _
1) Consider a uniform volumetric charge density 0 confined t

Problem 1:
Since the charge is uniform in the sphere, the distribution of the field must be
radial. So the field has only radial direction, i.e. E ER R . The Gauss law states
that:
E ndS
S
0
V
0dV
(1).
Consider an imaginary spherical surface, the radius

Problem 1 [Homework 6].
Consider a line charge distributed on straight line l z l . Find the electric field E using
two methods:
a) Find the electric potential V based on superposition (integration) and then the electric
field as E V
b) Find E directly ba