Resistors come in all shapes and sizes….
Different sizes mean
• Different values of
resistance
• Different amount of
electrical power dissipated
as heat
Resistors – inhibit (or resist) flow of
charges.
Current - Net flow of charge
Clicker Question #1
Which of these diagrams indicate the largest net current?
E) The current is the same in all of the
above.
E
Clicker Question #2
Which of these diagrams indicate a current going from left to right?
E) A and D
E
Microscopic model: 1) electric field accelerates charge 2) collisions with obstacles
scatters charges into another (random) direction. (3) electric field accelerates charge.
NET results is slow drifting motion of charge in direction of acceleration.
Clicker Question #3
What is the equivalent resistance of the network below?
A)
B)
C)
D)
E)
2.95 Ω
11.7 Ω
35 Ω
42 Ω
Impossible to tell. Resistors not in
series or parallel
E
Clicker Question #4
Given that the equivalent resistance is 11.7 Ω, how much power is dissipated by the
5 Ω resistor if Vab=10 volts?
A)
B)
C)
D)
E)
Exactly Zero
3.7 Watts
8.5 Watts
11.7 Watts
20 Watts
E
Kirchhoff’s loop laws: NET flow into a junction is zero.
I
j
0
j
For THIS
example
I1  I 2  I3  0
Clicker Question #5
What is correct junction equation for the following junction?
A) I  I  I  I  0
1
B)
2
3
4
I1  I 2  I3  I 4  0
C)
I1  I 2  I3  I 4  0
D)
 I1  I 2  I 3  I 4  0
B
E) None of the above
A
C
Clicker Question #6
For the given ASSUMED directions of the currents, what is the loop equation for the
TOP loop going clockwise around the loop?
A) 14  6 I  10  4 I  0
1
B)
2
14  6 I1  10  4I 2  0
C) 14  6 I1  10  4 I 2  0
D)
14  6I1  10  4I 2  0
B
E) None of the above
A
C