Free Mobile Device Hardware practice questions

A swollen/bulging battery is a serious safety hazard and can rupture, catch fire, or explode if mishandled. The correct response is to immediately stop use and charging, isolate the device away from flammables, handle it minimally, and proceed with safe service and proper hazardous disposal. Puncturing or compressing a swollen battery can trigger thermal runaway. Continuing to charge (even slowly) increases risk. Cooling may temporarily reduce temperature but does not correct internal gas generation and can add condensation risks; it does not make the battery safe to use.

Internal batteries are often held with adhesive, and controlled heat can help soften adhesive for safer removal. The safest practice is to use non-metal tools, disconnect the battery connector from the system board as early as possible to reduce electrical hazards, and avoid puncturing or bending the battery because physical damage can lead to thermal runaway. Metal prying tools increase the chance of shorting or puncturing cells. Keeping the battery connected longer increases risk during disassembly. Excessive continuous heat can exceed safe temperatures and increase degradation or hazard, and forceful removal increases the chance of puncture.

A lithium battery at 71% of its original capacity with roughly 900 cycles is worn out; its voltage sags under load, so the phone hits its cutoff early and reboots showing a much lower percentage. The fix is a battery replacement. Deliberately draining to 0% is nickel-chemistry advice that stresses lithium cells and does not restore lost capacity. Fast charging adds heat and accelerates wear rather than fixing reporting. A factory reset changes software only and cannot recover capacity the cell has physically lost.

Rapid drain following new app installs strongly suggests software-related causes such as background applications, excessive syncing, scanning services, or poorly designed apps preventing proper sleep states. The least invasive best-first step is to check battery usage statistics to identify the culprit and then limit background activity or remove the problematic apps. Replacing the battery is premature when health is normal. Disabling the BMS is unsafe and not a valid troubleshooting step. Increasing brightness increases power draw and worsens runtime.

Air travel compliance commonly references the battery’s energy capacity in watt-hours (Wh). Wh is calculated using Wh = (V × mAh) / 1000. For 15.2V and 6600mAh: (15.2 × 6600) / 1000 = 100.32Wh. That is slightly above 100Wh, which may require special approval depending on airline/regulations. The other choices use incorrect formulas or confuse voltage with capacity. Charge cycles are unrelated to carry-on energy limits.

M.2 drives are designed to be removed by sliding them straight out of the connector at the angle created by spring tension after the retaining screw is removed. Pulling upward or rotating downward risks damaging the connector or card.

Clicking noises are a hallmark of mechanical failure in HDDs, caused by failing read/write heads or platters. Combined with poor performance metrics, this strongly indicates HDD failure rather than SSD-related or software issues.

An M.2 NVMe SSD uses the PCIe bus, providing significantly higher performance than SATA-based options. Cloning minimizes user reconfiguration. A 2.5-inch SATA SSD or higher RPM HDD would offer less performance gain, and using the HDD as the boot drive negates the benefit of the NVMe slot.

A B+M keyed SATA M.2 SSD has notches for both keys, so it fits a B-keyed socket, and it speaks SATA, which is the only interface this socket is wired for. An M-keyed drive has the wrong notch and will not physically insert into a B-key socket. A B+M keyed PCIe x2 NVMe drive would fit, but the socket carries no PCIe lanes, so it would never be detected. A U.2 drive needs PCIe as well and adds an adapter the slot cannot support.

Frequent application reloads during multitasking indicate RAM pressure, where the OS terminates background apps to free memory. Fast relaunch times suggest storage performance is not the issue. Corruption or OS age is not supported by the symptoms.