[logo] SCEN103 Final Exam

Dec. 19, 1996

For full credit, work must be shown, including formulas used and algebraic and numerical steps. Answers must include units.

One 3" x 5" note card is permitted for this exam. Otherwise, the exam is closed book.

The note card must be turned in with the final exam.

Please check the most appropriate answer to the following statement:
I found the note card to be

1. (1 pt.)
From the Dec. 18, 1996 New York Times article "Drafting an Alphabet for the Digital Tradition":

Unicode is a fairly simple system that builds on the 128 characters of the 7-bit American Standard Code for Information Interchange (ASCII) and 256 characters of Latin-1, an 8-bit system also known as ISO 8859-1.

With 16 bits, Unicode is capable of encoding up to ______ characters, which is enough to represent most modern scripts.

Fill in the blank with the correct number. Show work below!

2. (1 pt.)
Many cars are now equipped with small resistance elements on their rear windows to melt ice and to prevent condensation by electrically heating the glass above the ambient temperature. I noticed this morning that several of the wires in my rear window were not working but the rest were heating properly. Are these wires connected in series to the 12 V battery or are they connected in parallel? Explain.

3. (1 pt.)
What does semiconductor physics have to do xerography, the process behind photocopying?

4. (2 pt.)
Discuss how "scratch resistance" is accomplished in the design of the compact disk. (A drawing would be nice...)

5. (1 pt.)
[comparison of CD and DVD]
The diagram on the left represents the pit/land dimensions on a standard CD-ROM, with storage capacity about 680 MB. The diagram on the right represents the new DVD format, with single-layer storage of 4700 MB. How much of the increase in storage capacity comes from making the pits smaller and closer together?

6. (1 pt.)
Describe how the bits of information are stored on a CD. What distinguishes the 0's from the 1's?

7. (3 pt.)
Construct the truth table for the following combination of gates: [Schematic of XOR gate]

What logic operation does this circuit accomplish?

8. (3 pt.)
Construct the truth table for the combination of transistor switches shown below by indicating the on/off state of each transistor and the final output state for the four different input possibilities.
(Remember that n-channel MOSFETs are turned on by application of a positive voltage (HI); p-channel MOSFETs by application of ground (LO).

[4 switches for NAND]

Which common logic gate does the circuit represent?

9. (4 pt.)
Consider the circuit below, consisting of a 9.0 V battery and two resistors, 12 ohm and 6 ohm.

[Circuit schematic]

a. What is the voltage across the 12 ohm resistor?

b. What is the current through the 6 ohm resistor?

c. What is the power dissipated by the 12 ohm resistor?

d. What is the power provided by the battery?

10. (2 pt.)
Electrons and nuclei compose atoms and atoms compose molecules. Molecules compose our bodies.

Is our mass primarily electronic or nuclear?

Is our size primarily electronic or nuclear?

11. (1 pt.)
Write briefly about why you are thankful for the Pauli exclusion princple and how it affects your daily life.

Last updated Dec. 19, 1996.
Copyright George Watson, Univ. of Delaware, 1996.