professors schmitz, haken, and minin ece 110 february 11, 2013

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Professors Schmitz, Haken, and Minin ECE 110 February 11, 2013

Hour Examination #1

1) Write your official:

Last Name (use capital letters):____Solution Key___________________

First Name (use capital letters):_________________________________

NetID:_____________________________________________________

UIN:_______________________________________________________

2) Fill in the Orange bubble sheet with all the information requested:

a. LAST NAME, FIRST INITIAL example: SCHMITZ C

b. STUDENT NUMBER (UIN) example: 678912345

c. SECTION (AL1 9am enter 111, AL2 1pm enter 222, AL3 3pm enter 333)

d. NETWORK ID (NetID) example: cdschmit

e. Also, fill out the hand-written center of the sheet with course,

instructor, section and your signature.

DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD

A. Write or print clearly in this exam booklet for your own benefit. Circle the correct answer

within the exam booklet and then mark it on the orange bubble sheet. You may not argue

for points because you marked one answer in the exam and another on the bubble sheet,

so be careful when marking your answers.

B. All problems are equally weighted.

C. Your grade will be determined based on the answers submitted on your bubble sheet.

Submit both the bubble sheet AND the complete exam booklet.

Students caught cheating on this exam will earn a grade of F for the entire course. Other

penalties may include suspension and /or dismissal from the university.

I have read and acknowledge the above statements. Furthermore, I promise not to give or

receive help on this or any other exam.

___________________________________________

Signature

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You have TEST FORM :

A Please enter this in the lower right corner of the orange bubble sheet in the location marked

TEST FORM.

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For the next two problems, consider circuit shown below.

Using the variables and defined above, answer these questions about circuit :

1. According to circuit ’s I-V characteristic, what is when = 0?

a. 12 V

b. 8 V

c. 0 V

d. -8 V

e. -12 V

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Full IV Characteristics:

: 12 − 2 − 4 = 0 : + = ⇒ = − ℎ: =

4 ⇒ = 4 −

⇒ : 12 − 2 4 − − 4

4 = 0

12 − 2 + 2 − = 0

2 = 32 − 12

= 34 − 6

!"# $%& '(ℎ%( )%&& ℎ*$: = 0 ⇒ = /ℎ′: 12 − 2 − 4 = 0 6 = 12 = +2 - = ℎ.: = × 4 = 2 × 4 = 8 &(

Easiest:

12: 46 ⋅ 12 = 8


a. 6 A

b. 2 A

c. 0 A

d. -2 A

e. -6 A (see IV characteristic above)

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For the next two problems, consider circuit shown below.

Find the full IV char:

: + 4 = 0 ℎ.: + 6 = 0 = − 1

6

Using the variables and defined above, answer these questions about circuit :


a. 12 V

b. 8 V

c. 0 V

d. -8 V

e. -12 V


a. 6 A

b. 2 A

c. 0 A

d. -2 A

e. -6 A

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For the next two problems, consider circuits and which are now connected

together as shown below.

Set IV equations equal to each other: = 5 − 6 = −

4 ⇒ = 6 ⇒ =

6 = 6.54. Substitute this back into either equation for : = −

4or

5

− 6

5. For the combined circuit, what is ?

a. 10

b. 8

c. :. ;<= Could also solve without IV data using VDR & Ohm’s.

d. 0

e. −5.33

6. For the combined circuit, given the answer from the previous problem,

what is the value of ?

a. >

-

b. −?

:@

c. >

A-

d. −A×>

-

e. 4××>

A-

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7. Consider the circuit below.

Find an equation that describes current .

a. =BC

BDEBF⋅ 3-

b. =BDEBF

BC⋅ 3-

c. =BD

BCEBF⋅ 3-

d. =BF

BD⋅ 3-

e. GH =IJ

IHEIJ⋅ J@

12: =2KL

2

⋅ 3 =

2 ⋅ 25

2 + 25

2

⋅ 3 =25

2 + 25

⋅ 3-

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8. Consider the resistor network below with nodes labeled A, BandC.

2KL = 2T//(2T + 2T)

=2T(2T+ 2T)

32T

=22T

32T=2

32T = 50

2T =3

2⋅ 50 = 75Ω

Note that 2YZ > 2T ⇒ (*) is only possibility.

Choose 2T such that 2YZ = 2Y\ = 2Z\ = 50Ω.

a. I] = ^;_

b. 2T = 33.3Ω

c. 2T = 25Ω

d. 2T = 16.7Ω

e. 2T = 8.33Ω

9. Consider the resistor network below.

2KL = 2 +(2 + 50)(2 + 50)

2(2 + 50)= 2 +

2

2+ 25 = 50

2 =32

2= 25 ⇒ 2 =

50

3Ω

Choose 2 such that 2YZ = 50Ω.

a. 2 = 50Ω

b. 2 = 25Ω

c. I =;`

J_

d. 2 =aA

4Ω

e. None of these.

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For the next four problems, consider the circuit shown below.

10. How many total loops could be formulated using KVL?

a. 1

b. 2

c. 3 (by inspection)

d. 4

e. 5

11. How many of these loops are independent?

a. 1

b. 2 (noting that two loops can touch each element…or, using b-n+1)

c. 3

d. 4

e. 5

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(Figure repeated from previous page…)

12. Which elements do not conform to the standard reference system (SRS)?

a. The current source only.

b. The current source and all the resistors.

c. The voltage source.

d. The current source and the voltage source.

e. 2and25.

13. If 2 = 10Ω,R = 2Ω, 25 = 4Ω, and2 = 6Ω, what is the value of ?

a. 6-

b. 2-

c. `@

d. −2-

e. −6-

ℎ: 4 + 6 + 45 = 0

: 5 + 1 =

c$#: 4 + 6 + 4( − 1) = 0 ⇒ = 0-

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For the next five problems, consider the following diagram where a wire is

carrying a non-zero current, I, in a permanent uniform magnetic field, d. Four

points of interest on the wire are labeled A, B, C, and D.

14. Find the direction of the force acting on the wire due to the current near

location A.

a. Up the page

b. Down the page

c. Into the page

d. Out of the page

e. There is no force.


location B.

a. Left

b. Right

c. Into the page

d. Out of the page


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Near B, the current and magnetic field are parallel and × d = 0. Near D,

× d = ⋅ d ⋅ sin(g) < ⋅ d but in the same direction.


location C.

a. Up the page

b. Down the page

c. Into the page

d. Out of the page


17. Because of the net forces, the wire will have a tendency to __________.

a. rotate

b. move up the page

c. move down the page

d. move left

e. move right

18. How does the force due to the current near location D compare to the force

due to the current near location A?

a. Same direction, smaller magnitude

b. Same direction, larger magnitude

c. Different direction, smaller magnitude

d. Different direction, same magnitude

e. Different direction, larger magnitude

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19. In the picture below, the periodic voltage waveform has a “square” shape

with the peak at 3, while the corresponding “saw-tooth” current waveform

has the peak of 1-. The period of each is unknown.

What is the average power of this waveform?

a. 3i

b. 1.5i

c. `. ^;j =

k

H⋅l

H⋅JE`

l

HEl

H

=

k

<l⋅J

l=

J

<j

d. 0.5i

e. 0i

20. A circuit, consisting of an ideal voltage source and resistors, has an I-V

curve with the intercepts at (0, 100-) and (3, 0-). If it were

connected to a 50 Ω load, what would be the magnitude of the current

through that load?

a. 187.5-

b. 150-

c. 100-

d. 60-

e. J^. ;m@ We can use = −A.

5 + 0.1 plus )50Ω: =

aA &

find the intercept = −A.

550 + 0.1. The plot is .

professors schmitz, haken, and minin ece 110 february 11, 2013

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