Comprehensive A+ Exam Review – Mobile, Networking, Hardware, Virtualization & Troubleshooting

A curated set of 80 question-and-answer flashcards spanning mobile device repair, connectivity, networking fundamentals, hardware components, storage, virtualization, cloud, and troubleshooting topics likely to appear on the CompTIA A+ (220-1101/1102) exam. The cards emphasize definitions, procedures, port numbers, standards, and best practices for quick study and self-testing.

What three safety steps must you always perform before opening a laptop for internal work?

Power the unit completely off, disconnect the AC adapter, and remove the battery.

Why is ESD protection (mat or wrist-strap) critical when replacing laptop components?

It safely discharges static electricity so it cannot arc into sensitive parts such as the motherboard, RAM, or SSD and permanently damage them.

After installing a new laptop battery, what two follow-up actions should you take?

Fully charge the battery and perform a calibration cycle so the OS can display accurate charge levels.

Which laptop component replacement often surprises technicians with extra disassembly and fragile ribbon cables?

Keyboard replacement.

At what angle do you normally insert SO-DIMMs or mini-PCIe Wi-Fi cards into a laptop slot?

About 30–45 degrees, then press them down to lock.

Before swapping an SSD/HDD, what two preparations reduce the risk of data loss?

Back up existing data and create/obtain OS installation or recovery media.

What makes Wi-Fi antenna repairs on laptops tricky?

The antennas snake around the display frame; incorrect routing or placement degrades signal strength.

State two advantages of USB-C over Micro-USB/Mini-USB.

USB-C is reversible and supports higher power delivery/data/video (USB 3.x PD) compared to the slower, non-reversible older connectors.

What is the typical range of NFC and one common use?

Under 4 cm; it is widely used for contactless payments.

How does a docking station differ from a port replicator?

Docking stations often deliver power and extra features (e.g., GPU, charging) while port replicators simply break out additional ports without powering the laptop.

Which Wi-Fi generations operate only in the 5 GHz band?

802.11a and 802.11ac.

What are the three non-overlapping 2.4 GHz Wi-Fi channels in North America?

Channels 1, 6, and 11.

What wireless standard introduced MU-MIMO?

802.11ac (Wi-Fi 5).

Define APIPA and give its address range.

Automatic Private IP Addressing self-assigns an address when DHCP fails; range 169.254.0.1–169.254.255.254.

Which two pieces of information, besides an IP address, does a DHCP server usually hand out?

Subnet mask and default gateway (it can also supply DNS servers, lease time, etc.).

Explain the main difference between TCP and UDP.

TCP is connection-oriented with reliable delivery (three-way handshake, acknowledgements); UDP is connectionless and faster but offers no guaranteed delivery.

On what port does HTTPS run and why is it preferred over HTTP?

TCP port 443; it encrypts traffic with TLS, securing data in transit.

What DNS record routes email for a domain?

MX (Mail Exchange) record.

Which DNS records are used for email authentication and anti-spoofing?

SPF (in TXT), DKIM, and DMARC records.

List two differences between a router and a switch.

A router forwards packets between different networks using IP addresses and can perform NAT; a switch forwards frames within a LAN using MAC addresses.

What does PoE allow and name one common PoE-powered device.

Power over Ethernet delivers electrical power plus data over the same Ethernet cable; examples include VoIP phones, security cameras, and access points.

Identify the three private IPv4 ranges you must memorize.

10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.

Why is CAT6A preferred over CAT5e in modern networks?

CAT6A supports 10 Gbps at full 100 m lengths and has better noise immunity, future-proofing the cabling plant.

Single-mode fiber is best suited to what type of installation and why?

Very long-distance runs (tens of kilometers) because its small core and laser light minimize signal dispersion.

Name two visual differences between HDMI and DisplayPort connectors.

HDMI has a tapered 19-pin plug with no latch; DisplayPort is rectangular with one corner beveled and often includes a locking tab.

What connector is typically used with coaxial cable for cable Internet?

F-type screw-on connector.

Define DIMM and SO-DIMM and give a typical use case for each.

DIMM is a full-size desktop memory module; SO-DIMM is smaller for laptops or mini-PCs.

Why is ECC RAM used in servers?

It detects and corrects single-bit memory errors, improving reliability for mission-critical workloads.

List the spindle speeds common to consumer HDDs.

5400 RPM and 7200 RPM (10K/15K in enterprise drives).

Contrast SATA SSD and NVMe SSD in terms of interface and performance.

SATA SSDs use the slower SATA bus (~550 MB/s); NVMe SSDs use PCIe lanes via M.2/U.2 for multi-GB/s throughput and lower latency.

What RAID level offers no redundancy but the best read/write performance?

RAID 0 (striping).

Which RAID level can survive two simultaneous drive failures?

RAID 6 (striping with double parity).

Describe the purpose of the M.2 slot on a modern motherboard.

It provides a compact, high-speed interface for SSDs (SATA or NVMe) and other add-on cards such as Wi-Fi/Bluetooth modules.

Give one key difference between Intel LGA and AMD PGA desktop CPU sockets.

Intel LGA puts the pins on the socket (land grid), while AMD PGA has the pins on the CPU (pin grid).

What voltage rails are most important on an ATX PSU, and which one powers motors and GPUs?

3.3 V, 5 V, and 12 V; the 12 V rail powers motors, GPUs, and high-draw components.

Explain ‘80 Plus’ certification.

A voluntary PSU efficiency rating (Bronze, Silver, Gold, etc.) indicating minimum percentage of power converted to DC without waste heat at several load levels.

State two key advantages of modular PSUs.

Users connect only the cables needed, improving airflow and reducing cable clutter inside the case.

What does Secure Boot do?

UEFI feature that verifies digital signatures of bootloaders/OS files, preventing untrusted code from running at startup.

Name two signs of imminent HDD failure detected via S.M.A.R.T.

Increasing bad sector count and high operating temperature (others include reallocated sector events, slow seeks).

A PC powers on but emits continuous beeps with no video. What are two likely hardware culprits?

Faulty or improperly seated RAM and/or graphics card (GPU).

Why can swollen lithium-ion batteries be dangerous?

Gas buildup distorts the cell casing, risking rupture, fire, or chemical leakage.

Give two common causes of ‘garbled print’.

Corrupted/incompatible printer driver or faulty data cable causing communication errors.

Which print technology uses powdered toner fused by heat and pressure?

Laser printing.

What maintenance item is unique to laser printers and contains rollers and a heating assembly?

Fuser (often part of a maintenance kit).

List one maintenance task for inkjet print heads.

Run print-head cleaning cycles or manually clean/clog-free the nozzles.

Describe the main difference between a Type 1 and Type 2 hypervisor.

Type 1 (bare-metal) installs directly on hardware for enterprise efficiency; Type 2 installs atop a host OS for desktop/testing convenience.

Give one example each of a Type 1 and a Type 2 hypervisor.

Type 1 – VMware ESXi or Microsoft Hyper-V Server; Type 2 – Oracle VirtualBox or VMware Workstation.

Why are snapshots useful in virtual machine management?

They capture the VM’s state, allowing quick rollback after software tests or patch failures.

Define IaaS and give a common provider.

Infrastructure as a Service delivers virtualized servers, storage, and networks; examples include AWS EC2 or Microsoft Azure VMs.

What cloud model combines on-prem private resources with public cloud scalability?

Hybrid cloud.

Explain ‘elasticity’ in cloud computing.

The automatic ability to scale resources up or down in response to real-time demand.

How does MDM help secure BYOD smartphones?

It enforces policies like screen-lock, encryption, remote wipe, containerized corporate apps, and VPN/email configuration from a central console.

What tool is used to punch wires into a 110 block on a patch panel?

Punchdown tool.

Which handheld device helps find the best Wi-Fi channel and locate interference?

Wi-Fi analyzer.

What is the primary purpose of a loopback plug?

To diagnose and verify the operation of a network port by sending outgoing signals back to the NIC for self-test.

Describe two symptoms of port flapping.

Interface status rapidly toggles up/down and connected devices experience intermittent connectivity.

What display technology provides true blacks without a backlight?

OLED (Organic Light-Emitting Diode).

TN panels are popular for gaming primarily because of which performance metric?

Fast response times (low pixel latency).

Which display type offers the widest color gamut and viewing angles among common LCD variants?

IPS (In-Plane Switching).

What is MiniLED and one benefit over standard LED-backlit LCDs?

Uses much smaller, denser LEDs for backlighting; improves local dimming, contrast, and brightness closer to OLED performance.

What cable pin-outs must match at both ends of an Ethernet run to pass certification?

Either T-568A to T-568A or T-568B to T-568B for a straight-through cable.

Explain the purpose of a toner probe kit ("fox & hound").

The toner injects a trace tone onto a cable; the probe detects that tone, letting technicians locate, label, or follow the cable through walls/patch panels.

Which networking device aggregates and monitors log messages on UDP 514?

Syslog server.

What does AAA stand for in network security?

Authentication, Authorization, and Accounting.

Define VLAN and give one benefit.

Virtual Local Area Network logically segments switch ports into separate broadcast domains, improving security and reducing congestion.

What is the key signaling difference between cable modem (DOCSIS) and DSL?

Cable uses coaxial infrastructure sharing bandwidth; DSL uses twisted-pair telephone lines with separate frequency bands for voice and data.

Give two common causes of high network latency.

Network congestion and long/inefficient routing paths (also faulty hardware or wireless interference).

A projector suddenly goes dark; the fan is running. What hardware item is most likely failed?

Burned-out projection lamp/bulb.

What printer feature allows pages to print on both sides automatically?

Duplex printing.

Why must thermal printers use special paper, and what happens if you leave a receipt in a hot car?

They rely on heat-sensitive paper; excessive external heat can darken or erase the print.

State two common symptoms of overheating in a desktop PC.

Random shutdowns/reboots and system throttling or sluggish performance; may also emit high fan speeds or burning smell.

What BIOS/UEFI feature locks the firmware settings from unauthorized changes?

BIOS/UEFI password (or supervisor password).

When would you prefer RAID 10 over RAID 5?

When you need both high performance and high redundancy (e.g., database server) and have at least four drives available.

What is the purpose of a Trusted Platform Module (TPM)?

Provides hardware-based cryptographic functions and secure key storage for features like full-disk encryption and secure boot.

Explain the DORA process in DHCP.

Discover, Offer, Request, Acknowledge – the four-step exchange that leases an IP address to a client.

What port does RDP use, and what is its primary function?

TCP 3389; enables remote graphical desktop access to Windows systems.

Give one characteristic that distinguishes Containers from full VMs.

Containers share the host OS kernel, making them lighter and faster to start while still isolating applications.

Which mobile device symptom strongly suggests water damage has occurred?

Flickering/unresponsive screen combined with a tripped Liquid Damage Indicator (LDI) near the SIM tray or battery well.

Why can a dirty or mis-aligned pickup roller cause paper not to feed?

The roller loses friction with the paper stack, so sheets remain in the tray instead of advancing into the print path.

What two network stats does a Wi-Fi analyzer show to diagnose poor VoIP quality?

Jitter (packet delay variation) and signal-to-noise ratio (SNR).

List two reasons a VM might need additional virtual NICs.

To separate traffic onto different VLANs/subnets or to increase bandwidth/ redundancy for high-load applications.

Explain "metered egress" in public cloud billing.

Outbound data leaving the cloud provider is charged per GB; excessive egress can dramatically increase monthly costs.

Which IPv6 DNS record maps a hostname to an IPv6 address?

AAAA record (Quad-A).

Name one advantage and one drawback of impact printers.

Advantage: can print on multi-part carbonless forms; drawback: noisy and slow compared to modern printers.

What does a negative acknowledgment (NAK) in networking indicate?

That the received data was corrupted or not understood, prompting a retransmission or other corrective action.