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The midterm exam is closed book, closed notes. You have 50 minutes to complete the exam.
You must complete the exam by yourself without any assistance from others. If an incident of
academic dishonesty is discovered, the student or students involved will, at a minimum, receive a zero (0)
on the exam.
Grading:
Your scores on these questions will depend on the extent to which:
The answer is complete.
The answer demonstrates exemplary knowledge of the question.
The answer is clearly organized, readable, and easy for the reader to follow.
The answer is free of grammatical and spelling errors.
“Go confidently in the direction of your dreams! Live the life you’ve imagined.”
~ Henry David Thoreau
Honor Statement
“On my honor as a student, I have neither given nor received aid on this exam.”
<student print name> <student signature>
_____Olufemi Alli__________________ Olufemi Alli
___________________
On a scale of 1 – 5 (1 is easy, 5 is hard), this exam was
__5___.
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COSC290/502 Midterm Exam Summer 2022 Name:______________________ Date:_______
1. Multiple choice (3 points each, 30 points total). Circle the letter of your choice.
One gigabyte is how many bytes?
A. 2^10
B. 2^20
C. 2^30
D. 2^40
One microsecond is how many seconds?
A. 10-3
B. 10-6
C. 10-9
D. 10-12
How many bits are in a byte?
A. 2
B. 4
C. 8
D. 16
Which of these is the most basic of the Computer Level Hierarchy?
A. Assembly Language
B. System Software
C. Digital Logic
D. High-Level Language
What does RAM stand for?
A. Referencing Automated Machine
B. Regulated Artificial Mechanism
C. Resting Attribute Measure
D. Random Access Memory
Which of these is not a basic logic gate?
A. FOR
B. AND
C. NOT
D. OR
In Boolean logic, what will x + x’ always equal?
A. x
B. x’
C. 0
D. 1
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Select the number with the highest magnitude:
A. 1011111110012
B. 3478
C. 100010
D. FF0016
A decoder has n inputs. How many outputs does it have?
A. n
B. log n
C. n2
D. 2n
What logic gate is this?
E. NAND
F. NOR
G. XOR
H. XAND
2. Base Conversion (6 points each, 30 points total). Convert each number to the specified
base. You must show your work to receive full credit. You may use the back sides of the
exam paper if you need more space.
2.1 4238 to Base 10
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2.2 15310 to Base 2
2.3 111100112 to Base 16
2.4 2AA16 to Base 10
2.5 10016 to Base 2
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3. Circuits and Digital Logic Short Answer (10 points each, 40 points total)
3.1 Construct a truth table for the following circuit:
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3.2
a. What is this circuit?
b. Construct a truth table for this circuit. (hint: if you know what this circuit’s purpose is, you
won’t need to use the diagram!)
This circuit is a Full Adder.
B.
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3.3
a. What is this circuit?
b. If S0 = 1 and S1 = 1, which input is transferred to the output?
3a.This circuit is a 4-to-1 Multiplexer (MUX).
B. If S0 = 1 and S1 = 1, which input is transferred to the output?
When both S0 and S1 are 1, the circuit selects the input corresponding to the binary value of S1S0 = 11, which
is input
ഖ
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I3.
Explanation:
In a 4-to-1 multiplexer, the selection lines determine which input is connected to the output.
The inputs are usually labeled as I0, I1, I2, and I3.
The selection lines S1 and S0 create a 2-bit binary number that selects one of the four inputs.
The binary number formed by S1 and S0:
00 selects I0
01 selects I1
10 selects I2
11 selects I3
Given that S0 = 1 and S1 = 1, the binary number formed is 11, which corresponds to input I3.
Therefore, if S0 = 1 and S1 = 1, the input
ഖ
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I3 is transferred to the output.
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3.4 What gate is this circuit logically equal to? Prove that this is the case.
The circuit is logically equivalent to an XOR
(Exclusive OR) gate.
To prove it logically, we can create the truth table
