Put your CompTIA A+ knowledge to the test with these 25 practice questions covering hardware, networking, mobile devices, troubleshooting, operating systems, and security. Each question includes a detailed explanation to reinforce your understanding and prepare you for the real exam.
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Questions 6–25 (Full Set)
Question 6: Which protocol operates at Layer 7 (Application) of the OSI model?
- A) TCP
- B) IP
- C) HTTP
- D) Ethernet
Click to reveal answer
Answer: C) HTTP — HTTP is an Application layer (Layer 7) protocol. TCP operates at Layer 4 (Transport), IP at Layer 3 (Network), and Ethernet at Layer 2 (Data Link).
Question 7: A user can ping IP addresses successfully but cannot browse any websites. What is the most likely issue?
- A) Default gateway is misconfigured
- B) DNS server is not responding
- C) DHCP server is down
- D) Network interface card is disabled
Click to reveal answer
Answer: B) DNS server is not responding — Since the user can ping by IP address, basic network connectivity is working. The inability to browse websites (which requires domain name resolution) points to a DNS issue.
Question 8: What is the default port number for HTTPS?
- A) 80
- B) 443
- C) 8080
- D) 3389
Click to reveal answer
Answer: B) 443 — Port 443 is the well-known default for HTTPS. Port 80 is HTTP, 8080 is an alternate HTTP port, and 3389 is used by Remote Desktop Protocol (RDP).
Question 9: Which wireless networking standard operates exclusively on the 5 GHz frequency band?
- A) 802.11b
- B) 802.11g
- C) 802.11ac (Wi-Fi 5)
- D) 802.11n (Wi-Fi 4)
Click to reveal answer
Answer: C) 802.11ac (Wi-Fi 5) — 802.11ac (Wi-Fi 5) operates exclusively on 5 GHz. 802.11b and 802.11g are 2.4 GHz only, and 802.11n (Wi-Fi 4) supports both 2.4 GHz and 5 GHz.
Question 10: Which network device is best suited to connect 15 computers in an office environment?
- A) Hub
- B) Switch
- C) Repeater
- D) Bridge
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Answer: B) Switch — A network switch is the standard device for connecting multiple computers in a LAN. Unlike hubs, switches intelligently forward traffic only to the intended destination port, providing better performance and security.
Question 11: A user reports that their smartphone battery drains unusually fast. What should a technician check FIRST?
- A) Replace the battery
- B) Check for background apps consuming power
- C) Perform a factory reset
- D) Update the operating system
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Answer: B) Check for background apps consuming power — Background apps are the most common cause of excessive battery drain and checking them is the least invasive first step. Replacing the battery, factory resetting, or updating the OS are more drastic measures to try later.
Question 12: Which technology provides the fastest data transfer between a mobile device and a computer?
- A) Bluetooth 5.0
- B) NFC
- C) USB-C
- D) Infrared (IR)
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Answer: C) USB-C — USB-C supports data transfer speeds up to 40 Gbps (with USB4/Thunderbolt). Bluetooth 5.0 maxes out around 2 Mbps, NFC at 424 kbps, and IR is a legacy technology with very low speeds.
Question 13: A user wants to wirelessly project their Android phone screen to a conference room display. Which technology should they use?
- A) Miracast
- B) Lightning
- C) HDMI
- D) Bluetooth
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Answer: A) Miracast — Miracast is a Wi-Fi Direct–based wireless display standard supported by Android devices. Lightning is an Apple-only connector, HDMI is a wired connection, and Bluetooth does not support screen mirroring.
Question 14: A desktop computer displays a ‘No boot device found’ error. What should a technician check FIRST?
- A) Replace the hard drive
- B) Check the BIOS/UEFI boot order
- C) Reinstall the operating system
- D) Update the BIOS firmware
Click to reveal answer
Answer: B) Check the BIOS/UEFI boot order — The BIOS/UEFI boot order is the simplest and most likely cause — the system may be trying to boot from the wrong device. This is the least invasive check before considering hardware replacement or OS reinstallation.
Question 15: A laptop displays a blank screen on its built-in display but works fine when connected to an external monitor. What is the most likely cause?
- A) Video card failure
- B) LCD panel or backlight failure
- C) Incorrect resolution setting
- D) Outdated display driver
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Answer: B) LCD panel or backlight failure — Since the external monitor works, the GPU and video output are functioning correctly. The issue is with the laptop’s own display hardware — either the LCD panel or the backlight has failed.
Question 16: Which command-line tool shows the path that packets take to reach a destination?
- A) ping
- B) ipconfig
- C) tracert
- D) netstat
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Answer: C) tracert — The tracert (traceroute) command shows each hop a packet takes on its way to a destination, including the IP address and response time of each intermediate router.
Question 17: A user’s PC is running slowly and the hard drive activity LED is constantly on. What is the most likely cause?
- A) Too many startup programs consuming resources
- B) A faulty network cable
- C) A monitor set to a high refresh rate
- D) An outdated keyboard driver
Click to reveal answer
Answer: A) Too many startup programs consuming resources — Excessive startup programs consume RAM and CPU resources, forcing the system to rely heavily on disk paging (swapping data between RAM and the hard drive), which causes constant HDD activity and poor performance.
Question 18: A user encounters a Blue Screen of Death (BSOD) after installing a new application. What should the technician try FIRST?
- A) Reinstall Windows
- B) Uninstall the recently installed application
- C) Replace the RAM modules
- D) Update the BIOS firmware
Click to reveal answer
Answer: B) Uninstall the recently installed application — The standard troubleshooting approach is to reverse the most recent change first. Since the BSOD began after installing a new application, uninstalling it is the logical first step.
Question 19: In Windows 10/11, which built-in tool is used to manage startup programs?
- A) msconfig
- B) Task Manager — Startup tab
- C) Device Manager
- D) Services.msc
Click to reveal answer
Answer: B) Task Manager — Startup tab — In Windows 10 and 11, the Task Manager’s Startup tab is the primary interface for enabling/disabling startup programs. While msconfig still exists, it redirects users to Task Manager for startup management.
Question 20: Which Windows feature allows you to repair the operating system without losing personal data?
- A) Clean install
- B) Reset this PC (Keep my files)
- C) System Restore
- D) Disk Cleanup
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Answer: B) Reset this PC (Keep my files) — “Reset this PC” with the “Keep my files” option reinstalls Windows while preserving the user’s personal files. System Restore reverts settings but doesn’t repair the OS, and a clean install erases everything.
Question 21: What file system is required for a UEFI system partition?
- A) NTFS
- B) FAT32
- C) exFAT
- D) ext4
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Answer: B) FAT32 — The UEFI specification requires the EFI System Partition (ESP) to be formatted as FAT32. This ensures cross-platform compatibility across different operating systems and hardware.
Question 22: Which command-line utility checks and repairs the Windows file system?
- A) sfc /scannow
- B) chkdsk /f
- C) diskpart
- D) format
Click to reveal answer
Answer: B) chkdsk /f — The chkdsk /f command checks the file system for errors and fixes them. sfc /scannow repairs system files (not the file system), diskpart manages partitions, and format erases drives.
Question 23: Which of the following is an example of multi-factor authentication (MFA)?
- A) Username and password
- B) Password and security question
- C) Password and fingerprint scan
- D) Two different passwords
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Answer: C) Password and fingerprint scan — Multi-factor authentication requires two or more different types of factors: something you know (password), something you have (token/phone), or something you are (biometrics). A password plus fingerprint combines “something you know” with “something you are.”
Question 24: A user receives an email appearing to be from their bank, asking them to verify their account by clicking a link. This is an example of:
- A) Spear phishing
- B) Phishing
- C) Vishing
- D) Whaling
Click to reveal answer
Answer: B) Phishing — This is standard phishing — a mass-distributed fraudulent email impersonating a trusted entity. Spear phishing targets specific individuals, vishing uses voice calls, and whaling targets high-profile executives.
Question 25: What is the best way to protect data on a laptop that might be stolen?
- A) Set a strong login password
- B) Use biometric authentication
- C) Enable full disk encryption
- D) Install a firewall
Click to reveal answer
Answer: C) Enable full disk encryption — Full disk encryption (such as BitLocker) encrypts the entire drive contents, making data unreadable without the correct decryption key — even if the drive is physically removed. Passwords and biometrics only protect the OS login, and firewalls protect against network threats, not physical theft.
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