WGU D684 Introduction to Computer Science
Study Guide 2025/2026 – Full Exam Preparation
WGU D684 Introduction to Computer Science: 100-Question Study Guide
Computer Architecture & Hardware
1. What is the primary function of the CPU?
A) Store data permanently
B) Execute program instructions ✓
C) Provide power to the computer
D) Display images on the monitor
2. Which component is considered volatile memory?
A) Hard Disk Drive (HDD)
B) Solid-State Drive (SSD)
C) Random Access Memory (RAM) ✓
D) Read-Only Memory (ROM)
3. What does the ALU (Arithmetic Logic Unit) within a CPU do?
A) Manages I/O operations
B) Performs mathematical calculations and logical comparisons ✓
C) Controls the fetch-decode-execute cycle
D) Stores the results of computations
4. Which bus is used to transfer data between the CPU and main memory?
A) Address Bus
B) Data Bus ✓
C) Control Bus
D) System Bus
5. What is the purpose of the clock speed in a CPU?
A) To tell the user the current time
B) To determine how many instructions a CPU can execute per second ✓
C) To regulate the CPU's temperature
D) To store temporary data
,6. What is a core in a multi-core processor?
A) A separate processing unit within a single CPU chip ✓
B) The speed at which the processor operates
C) The amount of cache memory available
D) The physical size of the CPU
7. Which memory type provides the fastest access for the CPU?
A) RAM
B) SSD
C) L1 Cache ✓
D) HDD
8. What is the primary role of the Control Unit (CU) in a CPU?
A) To perform arithmetic operations
B) To direct the operation of the processor by interpreting instructions ✓
C) To provide permanent storage for the OS
D) To connect to peripheral devices
9. Which component holds the boot-up firmware for the computer?
A) RAM
B) SSD
C) BIOS/UEFI chip ✓
D) GPU
10. What does "volatile" mean in the context of computer memory?
A) It is very fast.
B) It loses its contents when power is turned off. ✓
C) It is physically large.
D) It is read-only.
Data Representation & Number Systems
11. What is the smallest unit of data in a computer?
A) Byte
B) Nibble
C) Bit ✓
D) Word
12. How many bits are in a single byte?
A) 4
B) 8 ✓
,C) 16
D) 1024
13. What number system is the foundation of all modern computing?
A) Decimal
B) Hexadecimal
C) Octal
D) Binary ✓
14. What is the decimal value of the binary number 1010?
A) 8
B) 9
C) 10 ✓
D) 11
15. What is the primary purpose of the hexadecimal number system in computing?
A) To perform arithmetic faster than binary
B) To represent binary data in a more human-readable form ✓
C) To store data more compactly than binary
D) To replace the decimal system
16. What does the ASCII standard define?
A) A set of machine language instructions
B) A standard for character encoding ✓
C) A protocol for network communication
D) A type of computer architecture
17. How is the decimal number 5 represented in 4-bit binary?
A) 1001
B) 0101
C) 1010
D) 0101 ✓
18. What is the two's complement used for?
A) Representing fractional numbers
B) Representing negative integers in binary ✓
C) Converting binary to hexadecimal
D) Increasing the range of positive numbers
19. Which of these best describes an integer overflow error?
A) Dividing a number by zero
, B) A calculation produces a result that is too large to be represented in the allocated memory ✓
C) Losing precision when representing a floating-point number
D) A network packet that is too large
20. What is the hexadecimal digit 'F' equivalent to in decimal?
A) 15
B) 16 ✓
C) 17
D) 18
Operating Systems
21. What is the main function of an operating system?
A) To run application software
B) To manage the computer's hardware and software resources ✓
C) To provide a user interface
D) To protect against viruses
22. Which OS component is responsible for managing memory?
A) Kernel ✓
B) File System
C) Device Driver
D) User Interface
23. What is virtual memory?
A) A type of RAM that is very fast
B) Using part of the storage drive as an extension of RAM ✓
C) The memory used by the GPU
D) Memory that is not physically present
24. What is the purpose of a device driver?
A) To allow the OS to communicate with a specific hardware device ✓
B) To speed up the boot process
C) To manage user accounts
D) To compile source code
25. What is a process in an operating system?
A) A running instance of a program ✓
B) A thread of execution
C) A block of memory
D) A file on the disk
Study Guide 2025/2026 – Full Exam Preparation
WGU D684 Introduction to Computer Science: 100-Question Study Guide
Computer Architecture & Hardware
1. What is the primary function of the CPU?
A) Store data permanently
B) Execute program instructions ✓
C) Provide power to the computer
D) Display images on the monitor
2. Which component is considered volatile memory?
A) Hard Disk Drive (HDD)
B) Solid-State Drive (SSD)
C) Random Access Memory (RAM) ✓
D) Read-Only Memory (ROM)
3. What does the ALU (Arithmetic Logic Unit) within a CPU do?
A) Manages I/O operations
B) Performs mathematical calculations and logical comparisons ✓
C) Controls the fetch-decode-execute cycle
D) Stores the results of computations
4. Which bus is used to transfer data between the CPU and main memory?
A) Address Bus
B) Data Bus ✓
C) Control Bus
D) System Bus
5. What is the purpose of the clock speed in a CPU?
A) To tell the user the current time
B) To determine how many instructions a CPU can execute per second ✓
C) To regulate the CPU's temperature
D) To store temporary data
,6. What is a core in a multi-core processor?
A) A separate processing unit within a single CPU chip ✓
B) The speed at which the processor operates
C) The amount of cache memory available
D) The physical size of the CPU
7. Which memory type provides the fastest access for the CPU?
A) RAM
B) SSD
C) L1 Cache ✓
D) HDD
8. What is the primary role of the Control Unit (CU) in a CPU?
A) To perform arithmetic operations
B) To direct the operation of the processor by interpreting instructions ✓
C) To provide permanent storage for the OS
D) To connect to peripheral devices
9. Which component holds the boot-up firmware for the computer?
A) RAM
B) SSD
C) BIOS/UEFI chip ✓
D) GPU
10. What does "volatile" mean in the context of computer memory?
A) It is very fast.
B) It loses its contents when power is turned off. ✓
C) It is physically large.
D) It is read-only.
Data Representation & Number Systems
11. What is the smallest unit of data in a computer?
A) Byte
B) Nibble
C) Bit ✓
D) Word
12. How many bits are in a single byte?
A) 4
B) 8 ✓
,C) 16
D) 1024
13. What number system is the foundation of all modern computing?
A) Decimal
B) Hexadecimal
C) Octal
D) Binary ✓
14. What is the decimal value of the binary number 1010?
A) 8
B) 9
C) 10 ✓
D) 11
15. What is the primary purpose of the hexadecimal number system in computing?
A) To perform arithmetic faster than binary
B) To represent binary data in a more human-readable form ✓
C) To store data more compactly than binary
D) To replace the decimal system
16. What does the ASCII standard define?
A) A set of machine language instructions
B) A standard for character encoding ✓
C) A protocol for network communication
D) A type of computer architecture
17. How is the decimal number 5 represented in 4-bit binary?
A) 1001
B) 0101
C) 1010
D) 0101 ✓
18. What is the two's complement used for?
A) Representing fractional numbers
B) Representing negative integers in binary ✓
C) Converting binary to hexadecimal
D) Increasing the range of positive numbers
19. Which of these best describes an integer overflow error?
A) Dividing a number by zero
, B) A calculation produces a result that is too large to be represented in the allocated memory ✓
C) Losing precision when representing a floating-point number
D) A network packet that is too large
20. What is the hexadecimal digit 'F' equivalent to in decimal?
A) 15
B) 16 ✓
C) 17
D) 18
Operating Systems
21. What is the main function of an operating system?
A) To run application software
B) To manage the computer's hardware and software resources ✓
C) To provide a user interface
D) To protect against viruses
22. Which OS component is responsible for managing memory?
A) Kernel ✓
B) File System
C) Device Driver
D) User Interface
23. What is virtual memory?
A) A type of RAM that is very fast
B) Using part of the storage drive as an extension of RAM ✓
C) The memory used by the GPU
D) Memory that is not physically present
24. What is the purpose of a device driver?
A) To allow the OS to communicate with a specific hardware device ✓
B) To speed up the boot process
C) To manage user accounts
D) To compile source code
25. What is a process in an operating system?
A) A running instance of a program ✓
B) A thread of execution
C) A block of memory
D) A file on the disk
