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Mobile Devices — A+ Core 1 practice questions

Domain 1 of the CompTIA A+ Core 1 (220-1101) exam. 138 questions on this domain in the full bank — here are four free samples with answers and explanations.

Question 1 · Difficulty 2/5

A technician is replacing a swollen battery in a thin ultrabook and notices the failed cell is housed in a flexible foil pouch rather than a rigid metal can. Which physical characteristic correctly describes this battery type and distinguishes it from a traditional lithium-ion cell? (Select the best answer.)
  1. Lithium-polymer batteries use a liquid electrolyte sealed inside a rigid metal cylindrical cell.
  2. Lithium-polymer batteries use a gel or solid polymer electrolyte and are packaged in a flexible foil pouch.
  3. Lithium-polymer batteries use a liquid electrolyte but are enclosed in a prismatic hard-shell aluminum housing.
  4. Lithium-polymer batteries use a liquid electrolyte but are sealed in a prismatic hard-plastic housing.
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Correct answer: B

Lithium-polymer batteries use a gel or solid polymer electrolyte and are packaged in a flexible foil pouch.
Lithium-polymer (LiPo) cells use a gel or solid polymer electrolyte rather than a liquid electrolyte, and they are packaged in a lightweight flexible foil pouch, which allows them to be manufactured in thin, custom shapes suited to slim ultrabooks. Traditional lithium-ion cells use a liquid electrolyte and are typically sealed in rigid cylindrical or prismatic metal or hard-plastic housings. The choice describing a liquid electrolyte sealed inside a rigid metal cylindrical cell describes a cylindrical Li-ion cell, not a LiPo design. The choice describing a liquid electrolyte enclosed in a prismatic hard-shell aluminum housing describes a prismatic hard-shell aluminum Li-ion cell, which also uses liquid electrolyte and a rigid enclosure. The choice describing a liquid electrolyte sealed in a prismatic hard-plastic housing describes a standard Li-ion prismatic cell with a hard-plastic housing, again, not a lithium-polymer design.

Question 2 · Difficulty 3/5

A technician opens a customer's laptop for a routine cleaning and notices that the built-in lithium-polymer battery is visibly swollen, causing the bottom cover to bow outward. What is the correct immediate action? (Select the best answer.)
  1. Discharge the battery to 0% using the operating system's battery report tool, then continue normal service.
  2. Puncture the swollen pouch to release the internal gas pressure before removing the battery.
  3. Remove the swollen battery from the laptop immediately using ESD precautions and handle it as a hazardous material, then replace it before returning the device to service.
  4. Reinstall the bottom cover and advise the customer to replace the battery within the next 30 days at their convenience.
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Correct answer: C

Remove the swollen battery from the laptop immediately using ESD precautions and handle it as a hazardous material, then replace it before returning the device to service.
A swollen lithium-polymer battery indicates internal gas buildup caused by electrolyte breakdown, which creates a risk of thermal runaway, fire, or rupture. The battery must be removed immediately using ESD precautions to protect both the technician and the surrounding components, and it must be treated as a hazardous material (not placed in regular trash). Discharging a swollen battery to 0% does not eliminate the hazard and may accelerate the breakdown. Puncturing the pouch releases flammable electrolyte vapors and is extremely dangerous. Delaying replacement leaves an active safety risk with the customer.

Question 3 · Difficulty 3/5

Before beginning a battery replacement on a laptop, a technician consults the model-specific service manual rather than relying on a generic disassembly guide. Which of the following best explains why the model-specific service manual is necessary for a safe and correct battery swap? (Select the best answer.)
  1. Generic guides document ESD wrist strap grounding points that vary by manufacturer, which the model-specific manual corrects.
  2. The model-specific manual details the exact screw types, connector release sequences, adhesive pull-tab orientation, and any captive cable or ZIF connector locations unique to that model, preventing physical damage during disassembly.
  3. The model-specific manual provides the battery authentication chip bypass code needed to allow third-party batteries to charge.
  4. Only model-specific manuals list the lithium-polymer vs lithium-ion chemistry used, which is required to select the correct replacement part number.
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Correct answer: B

The model-specific manual details the exact screw types, connector release sequences, adhesive pull-tab orientation, and any captive cable or ZIF connector locations unique to that model, preventing physical damage during disassembly.
Modern laptops vary significantly in screw sizes, Torx vs Phillips head requirements, adhesive pull-tab locations and orientations, and the presence of fragile ZIF (zero insertion force) ribbon cable connectors or captive cables near the battery. Using the wrong disassembly sequence based on a generic guide can shear connectors, tear cables, or strip screws. The model-specific service manual (available from the OEM or sources such as iFixit for consumer devices) documents all of these details precisely. ESD grounding points are generally consistent across models and do not require a model-specific manual to locate. Authentication chip bypass codes are not a legitimate or documented service procedure. Battery chemistry is typically printed on the battery label itself and does not require a service manual to identify.

Question 4 · Difficulty 2/5

Which of the following best describes the purpose of a Zero Insertion Force (ZIF) connector used to attach a ribbon cable on a laptop keyboard? (Select the best answer.)
  1. It uses a locking screw to clamp the ribbon cable in place, preventing vibration damage.
  2. It allows the ribbon cable to be inserted and removed without applying lateral force to the cable contacts, reducing the risk of damage.
  3. It permanently bonds the ribbon cable to the motherboard using a conductive adhesive backing.
  4. It provides hot-swap capability so the keyboard can be replaced while the laptop is powered on.
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Correct answer: B

It allows the ribbon cable to be inserted and removed without applying lateral force to the cable contacts, reducing the risk of damage.
A ZIF connector uses a hinged locking arm (sometimes called a flip-lock or actuator) that, when opened, allows the ribbon cable to slide in or out with zero insertion force, protecting the delicate cable contacts. A locking screw is not part of ZIF connector design; that description applies to certain panel-mount connectors used in other applications. ZIF connectors are not adhesive; they are friction-released by lifting the actuator. ZIF connectors provide no hot-swap capability and the system should always be powered off before handling internal ribbon cables.

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