ee 211 sample exam

8/10/2019 EE 211 Sample Exam

1/12

page 1/12

The Pennsylvania State University

Department of Electrical Engineering

EE 211/EE 212

Sample Final Exam A

Student Name:

PSU ID #:

This exam is intended to give you practice solving problems that are typically found on final

exams. There are 20 multiple-choice problems covering the topics from lectures 3041.


2/12

page 2/12

Multiple choice questions; only one correct answer for each question.

1. Given the complex numbers 6ja and 9.3620b , compute bac and give the

result in rectangular form.

A. 4.58.0 j

B. 24 j

C. 616 j

D. 8.104 j

E. 10 +j6

2. Determine the angular frequency, , of the sinusoidal voltage signal shown in the figure.

A. rad/s81

B. rad/s8

C. rad/s6

D. rad/s4

E. rad/s4

1

0 2 4 6 8 10 12 14 16

-2

-1

0

1

2

time, seconds

voltage,volts


3/12

page 3/12

3. Determine the type and the value of a circuit element that has an impedance 25jZ

at 1000 rad/s.

A. 25-mH inductorB. 25-mF capacitor

C. 25-resistor

D. 40-mH inductor

E. 40-F capacitor

4. Determine the equivalent impedance at 1000 rad/s at terminalsA-Bin the circuit below.

A. jZeq 125

B. jZeq 125

C.

50150 jZ

eq

D. jZeq 150

E. jZeq 150

50 mH50

A

B


4/12

page 4/12

5. Determine the equivalent impedance at terminalsA-Bin the circuit below.

A.

6jZeq B. 23jZeq

C. 3jZeq

D. 6jZeq

E. 9jZeq

6. In the sinusoidal steady state circuit below, at what angular frequency will the voltageacross the current source be in phase with its current?

A. 0.2 rad/s

B. 0.4 rad/s

C. 2 rad/s

D. 5 rad/s

E. 100 rad/s

j3

A B

-j3 -j3

5 mF

10

iS(t) vS(t)+

20 mH


5/12

page 5/12

7. Determine the phasor current xI~

in the sinusoidal steady state circuit below.

A. A4.6353~

xI

B. A2.823~

xI

C. A905~

xI

D. A4.1810

~

xI

E. A13525~

xI

8. Use nodal analysis to determine the node voltage1

~V in the following sinusoidal steady

state circuit.

A. V4.1535

2~1 V

B. V6.2652~

1 V

C. V4.6352~1 V

D. V4.632~1 V

E. V4.632~1 V

j3

xI~

A63~

jIS

5jSV~

j3

105 j 5j

1

~V 5j

V02


6/12

page 6/12

9-10. For the following two questions, consider the sinusoidal

steady state circuit below. Some of the phasor voltages

and currents in the circuit are given in the phasor diagram

on the right. Note: The unit in the diagram is volt for thephasor voltage and ampere for the phasor currents.

9. Find the phasor current 1~I .

A. A02~

1 I

B. A902~

1 I

C. A902~

1 I

D. A1.5310~

1 I

E. A1.5310~

1 I

10. Which of the following circuit elements combinations would be appropriate model for theimpedanceZ2?

A. resistor and capacitor in series

B. resistor and inductor in series

C. resistor only

D. capacitor only

E. inductor only

2

~I

Re

Im

3

~I

2 4-4 -2

-4

-2

-6

2

4

-82

~V

1

~I Z1

Z3Z2

3

~I2

~I

2

~V

network


7/12

page 7/12

11. Determine the effective (RMS) value of the periodic waveform below.

A.

B. 3 Vrms

C.

D.

E. 4 Vrms

12. Which of the following statements about effective (RMS) value of a periodic signal is

false?

A. The RMS value is always greater than or equal to the average value.

B. The RMS value is always positive.

C. For a sinusoid, the RMS value is the signals magnitude divided by .

D. The RMS value ofx(t)is the same as forx(t).

E. For a sinusoid, the RMS value depends on the frequency of the sinusoid.

v(t)

8

44 V

4 t


8/12

page 8/12

13. The voltage supplied to a circuit is given by:

10cos 2 60 90inv t t V

If the current leaving this voltage source has an amplitude of 5 mA and lags behind the

voltage by 36.9o, determine the average power delivered by the source.

A. 0 mW

B. 20 mW

C. 25 mW

D. 40 mW

E. 50 mW

14. What should the load, ZL, be in order to achieve maximum power transfer to the load?

A. 2 F capacitance

B. 100 resistance in series with a 2 F capacitance

C. 100 resistance in series with a 0.5 H inductanceD. 0.5 H inductance

E. 100 resistance

ZL5cos(1000t)V

100 2 F

ZL5cos(1000t)V

100 2 F


9/12

page 9/12

15. A sinusoidal voltage source with amplitude Vis attached to two loads in parallel as shown

below. One of the loads is a pure resistance Z1= Rand the other load has an impedance

Z2= R+jX. Which statement below is false?

A. The average power absorbed by the pure resistance is given by

.

B. The load composed of a resistance and reactance will absorb less average power than

the pure resistance load.

C. If the load composed of a resistance and reactance had impedance Z2= RjX, the

amount of average power absorbed by that load would remain unchanged.

D. The average power delivered by the source is equal to the sum of the average powers

absorbed by the two loads.

E. The current exiting the voltage source will not be in phase with the voltage.

16. Determine I2in the circuit shown below:

A. 4 20 A

B. 8 20 A

C. 8 160 A

D. 10 20 A

E. 10 160 A


10/12

page 10/12

17. Determine Voin the circuit shown below:

A. 3.75j1.5 V

B. 1.17j2.73 V

C. 1.17 +j2.73 VD. 16.4j7.02 V

E. 16.4 +j7.02 V


11/12

page 11/12

18. In Figure A an electric range is connected to a single-phase residential AC source of 240

Vrmsand consumes 5 kW when operating normally. If the same range is connected between

phase a and b of a 3-phase power source, shown in Figure B, find the ratio of power

consumed by the range in Figure B to the power consumed in Figure A.

A.

B.

C. 1

D.

E. 3

Range

+

Figure A

1200V

139120V

139240V

Figure B

a

b

c

n

+

+

+

Range

+

1200V

1390V


12/12

page 12/12

19. The total complex power at the load of a 3-phase balanced system is 24 30 kVA. Find the

real power consumed by the load in watts.

A. 20.8 kWB. 12.0 kW

C. 24.8 kW

D. 10.0 kW

E. 13.8 kW

20. A man and his son are flying a kite. The kite becomes entangled in a 7200 V RMS power

line close to a pole. The man crawls up the metal pole to remove the kite and while holdingonto the pole with one hand his other hand accidentally comes in contact with the 7200 V

power line. Assuming dry skin with resistance of 15 k, arm resistance of 100 ,and good

contact with ground via the power pole, what is the potential current through the mans body?

A. 238 mA

B. 337 mA

C. 477 mA

D. 675 mA

E. 954 mA

ee 211 sample exam

Documents