San Jose State University
Department of Electrical Engineering
Exam 2
EE 140
Fall 2007
Closed Book, and Notes,
Instructions: There are 10 problems. Interpretation of questions will not be
given during the exam. If you are unsure about the meaning of a que
Chap'ie? E
Section i=3: Eraveiing Waves
Probﬁem 1.1 A 4-111-12 sound wave traveling in the x—direction in air was observed
to have a differential pressure p(x._ z) = 5 "ﬁlm2 at x = 0 and r z 25 ,us. If the reference
phase or" phat) is 42", ﬁnd a complete
CHAPTER 1
1.1. Given the vectors M = 10ax + 4ay 8az and N = 8ax + 7ay 2az , nd:
a) a unit vector in the direction of M + 2N.
M + 2N = 10ax 4ay + 8az + 16ax + 14ay 4az = (26, 10, 4)
Thus
a=
(26, 10, 4)
= (0.92, 0.36, 0.14)
|(26, 10, 4)|
b) the magnitude of
EE140
1.
Review Electrostatics
Dr. Ray Kwok
Consider two point charges (+Q, -Q) located along the x-axis as shown.
a. What is the electric potential at point P(2a,0)? (Note: there is no charge at point P.)
b. From this potential, derive an equation for th
EE 140
Solution
exercise in Intro slides
Dr. Ray Kwok
Exercise - 1
Find:
(a)
(b)
(c)
(d)
(e)
(f)
A B
B 2A
A B
A B
A A
BB
A x 4 z
B 2 x y z
(g) Angle between A and B
(h) Find a vector that is perpendicular to A and B ?
A x 4 z
B 2 x y z
Exercise