WGU D684 OBJECTIVE ASSESSMENT FINAL LATEST
2026 ACTUAL EXAM TEST BANK| D684
INTRODUCTION TO COMPUTER SCIENCE OA FINAL
WITH 650 REAL EXAM QUESTIONS AND CORRECT
VERIFIED ANSWERS/ ALREADY GRADED A+ (MOST
RECENT!!)
1. What is binary?
A) A programming language
B) A numerical system using only digits 0 and 1
C) A type of data compression
D) A memory management technique
Correct Answer: B
Rationale: Binary is a base-2 number system that uses only two
digits (0 and 1). Computers use binary because transistors have
two natural states: on (1) and off (0).
2. What is ASCII used for?
A) Compressing images
B) Encrypting data
C) Encoding text characters as numeric values
D) Managing memory allocation
1
,Correct Answer: C
Rationale: ASCII (American Standard Code for Information
Interchange) assigns unique 7-bit or 8-bit numeric codes to
letters, digits, and symbols, enabling computers to store and
exchange text.
3. Which of the following is a lossless compression technique?
A) JPEG compression
B) MP3 compression
C) Run-length encoding
D) MPEG compression
Correct Answer: C
Rationale: Run-length encoding (RLE) replaces repeated
sequences with a count and a single value, allowing perfect
reconstruction of original data. JPEG, MP3, and MPEG are
lossy—they permanently discard some information.
4. What does Unicode provide that ASCII does not?
A) Faster processing speed
B) Support for characters from virtually all writing systems
worldwide
C) Built-in encryption
D) Smaller file sizes
2
,Correct Answer: B
Rationale: ASCII only supports 128-256 characters (English
letters, digits, symbols). Unicode supports over 143,000
characters from all major world scripts, including emoji.
5. The term "overflow" in computing refers to:
A) A condition where memory runs out of space
B) A calculation exceeding the maximum representable value for
a given number of bits
C) A network data transmission error
D) A syntax error in programming
Correct Answer: B
Rationale: Overflow occurs when an arithmetic operation
produces a result larger than what can be stored in the allocated
number of bits, causing unexpected behavior or errors.
6. What is the compression ratio?
A) The time required to compress a file
B) The ratio of original data size to compressed data size
C) The amount of memory used during compression
D) The number of bits per second in a transmission
Correct Answer: B
Rationale: Compression ratio indicates how effectively data has
3
, been reduced. A ratio of 10:1 means the compressed file is one-
tenth the size of the original.
7. What is the primary difference between lossless and lossy
compression?
A) Lossless works only on text; lossy works only on images
B) Lossless preserves all original data; lossy discards some data
to achieve smaller file sizes
C) Lossless is faster than lossy
D) Lossless requires more processing power
Correct Answer: B
Rationale: Lossless compression allows perfect reconstruction (e.g.,
ZIP files). Lossy compression reduces file size more by removing
imperceptible data but cannot restore original quality (e.g.,
JPEG).
8. Huffman encoding is a compression technique based on:
A) Replacing repeated characters with a single character and
count
B) Using variable-length codes based on character frequency
C) Reducing color depth in images
D) Removing high-frequency sounds
4
2026 ACTUAL EXAM TEST BANK| D684
INTRODUCTION TO COMPUTER SCIENCE OA FINAL
WITH 650 REAL EXAM QUESTIONS AND CORRECT
VERIFIED ANSWERS/ ALREADY GRADED A+ (MOST
RECENT!!)
1. What is binary?
A) A programming language
B) A numerical system using only digits 0 and 1
C) A type of data compression
D) A memory management technique
Correct Answer: B
Rationale: Binary is a base-2 number system that uses only two
digits (0 and 1). Computers use binary because transistors have
two natural states: on (1) and off (0).
2. What is ASCII used for?
A) Compressing images
B) Encrypting data
C) Encoding text characters as numeric values
D) Managing memory allocation
1
,Correct Answer: C
Rationale: ASCII (American Standard Code for Information
Interchange) assigns unique 7-bit or 8-bit numeric codes to
letters, digits, and symbols, enabling computers to store and
exchange text.
3. Which of the following is a lossless compression technique?
A) JPEG compression
B) MP3 compression
C) Run-length encoding
D) MPEG compression
Correct Answer: C
Rationale: Run-length encoding (RLE) replaces repeated
sequences with a count and a single value, allowing perfect
reconstruction of original data. JPEG, MP3, and MPEG are
lossy—they permanently discard some information.
4. What does Unicode provide that ASCII does not?
A) Faster processing speed
B) Support for characters from virtually all writing systems
worldwide
C) Built-in encryption
D) Smaller file sizes
2
,Correct Answer: B
Rationale: ASCII only supports 128-256 characters (English
letters, digits, symbols). Unicode supports over 143,000
characters from all major world scripts, including emoji.
5. The term "overflow" in computing refers to:
A) A condition where memory runs out of space
B) A calculation exceeding the maximum representable value for
a given number of bits
C) A network data transmission error
D) A syntax error in programming
Correct Answer: B
Rationale: Overflow occurs when an arithmetic operation
produces a result larger than what can be stored in the allocated
number of bits, causing unexpected behavior or errors.
6. What is the compression ratio?
A) The time required to compress a file
B) The ratio of original data size to compressed data size
C) The amount of memory used during compression
D) The number of bits per second in a transmission
Correct Answer: B
Rationale: Compression ratio indicates how effectively data has
3
, been reduced. A ratio of 10:1 means the compressed file is one-
tenth the size of the original.
7. What is the primary difference between lossless and lossy
compression?
A) Lossless works only on text; lossy works only on images
B) Lossless preserves all original data; lossy discards some data
to achieve smaller file sizes
C) Lossless is faster than lossy
D) Lossless requires more processing power
Correct Answer: B
Rationale: Lossless compression allows perfect reconstruction (e.g.,
ZIP files). Lossy compression reduces file size more by removing
imperceptible data but cannot restore original quality (e.g.,
JPEG).
8. Huffman encoding is a compression technique based on:
A) Replacing repeated characters with a single character and
count
B) Using variable-length codes based on character frequency
C) Reducing color depth in images
D) Removing high-frequency sounds
4
