[Electrical Engineering Principles and Applications Allan Hambley 3rd Ed Pearson] electrical_eng_2

CHAPTER 1
Exercises

E1.1 Charge = Current × Time = (2 A) × (10 s) = 20 C

E1.2 ( ) ( ) (0.01sin(200t) 0.01 200cos(200t ) 2cos(200t ) A

dt
d
dt
i t = dq t = = × =

E1.3 Because i2 has a positive value, positive charge moves in the same

direction as the reference. Thus positive charge moves downward in
element C.
Because i3 has a negative value, positive charge moves in the opposite
direction to the reference. Thus positive charge moves upward in
element E.

E1.4 Energy = Charge × Voltage = (2 C) × (20 V) = 40 J

Because vab is positive, the positive terminal is a and the negative
terminal is b. Thus the charge moves from the negative terminal to the
positive terminal, and energy is removed from the circuit element.

E1.5 iab enters terminal a. Furthermore, vab is positive at terminal a. Thus

the current enters the positive reference, and we …(생략)

E1.6 (a) p (t ) v (t )i (t ) 20t 2 a = a a =

6667 J