220-1101 Mobile Devices Practice Test 13 — 15 Questions

Question 1

A user reports that the camera on their smartphone takes pictures but all images are completely black, even in well-lit conditions. The camera app does not show any error messages. The flash works, and the front camera functions normally. Which component is MOST likely faulty?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Camera sensor. The camera sensor is the component that converts light into an electronic signal to form an image. If the sensor is faulty, it will not capture any light data, resulting in completely black images regardless of lighting conditions. The fact that the flash works and the front camera functions normally isolates the issue to the rear camera sensor itself, not the software or other hardware.

Answer

Camera app software

Answer

Flash LED

Answer

Proximity sensor

Question 2

A user reports that their smartphone's Bluetooth has stopped working entirely—it cannot discover any devices and cannot be discovered by other devices. However, Wi-Fi connectivity remains unaffected. The technician has already performed a full network settings reset and tested the device in safe mode. Which of the following hardware components is MOST likely faulty?

Accepted Answer

Wi-Fi/Bluetooth combo chip. The Wi-Fi/Bluetooth combo chip is the most likely faulty component because both Wi-Fi and Bluetooth share the same integrated circuit in modern smartphones. Since Wi-Fi continues to work normally, the Bluetooth portion of the combo chip has failed internally, while the Wi-Fi path remains functional. A full network settings reset and safe mode test rule out software or driver issues, isolating the fault to the hardware.

Answer

Bluetooth antenna

Answer

Power management IC

Answer

Battery

Question 3

A user reports that their smartphone's battery drains very quickly even when the phone is idle. The technician checks battery health in settings and it shows 'Normal.' No single app reports excessive power consumption. The phone also feels warm to the touch while not in use. Which of the following is the MOST likely cause?

Accepted Answer

The phone is infected with malware. The phone feels warm while idle and drains battery quickly despite no single app showing high usage, which strongly suggests background activity from malware. Malware can run hidden processes, keep the CPU active, and maintain network connections, generating heat and draining power without appearing in standard battery usage lists. The battery health being 'Normal' rules out a faulty battery as the primary cause.

Answer

The battery is faulty and needs replacement

Answer

The operating system requires an update

Answer

The phone's charging port is damaged

Question 4

A user reports that their smartphone's earpiece speaker is extremely quiet during phone calls. The loudspeaker and Bluetooth audio work perfectly. The technician has already increased the in-call volume to maximum. Which of the following components is MOST likely faulty?

Accepted Answer

The earpiece speaker. The earpiece speaker is the most likely faulty component because the issue is isolated to the internal speaker used for phone calls, while the loudspeaker and Bluetooth audio work perfectly. This indicates that the audio signal path to the earpiece is compromised, but the audio amplifier chip and other audio outputs are functioning. The technician has already maximized the in-call volume, ruling out a software or user-setting issue.

Answer

The audio amplifier chip

Answer

The charging port

Answer

The proximity sensor

Question 5

A user reports that their smartphone's GPS is often inaccurate (location is off by several blocks) and the camera app crashes when switching to video mode. The phone has no physical damage and has not been dropped recently. The technician performs a factory reset, but the problems persist. Which of the following components is MOST likely faulty?

Accepted Answer

Main logic board. The main logic board (motherboard) integrates the GPS receiver, camera controller, and other subsystems. A fault here can cause seemingly unrelated issues—like GPS inaccuracy and camera crashes—because the board handles data routing and power distribution for multiple components. Since a factory reset did not resolve the problems, the hardware failure is likely on the logic board itself, not a peripheral module.

Answer

Camera module

Answer

GPS antenna

Answer

Battery

Question 6

A user reports that the touchscreen on their smartphone is unresponsive in a vertical strip approximately one inch wide, running from the top to the bottom of the screen. All other areas of the screen respond correctly to touch. The user has cleaned the screen and removed the screen protector. The phone has not been dropped or exposed to liquid. Which of the following components is MOST likely causing this issue?

Accepted Answer

Digitizer failure. The digitizer is the layer responsible for detecting touch input. A vertical strip of unresponsiveness, without any impact or liquid damage, indicates a localized failure of the digitizer's grid of electrodes, often caused by a manufacturing defect or internal crack in the digitizer layer itself. The LCD panel remains functional because the display still shows images correctly in that area.

Answer

LCD panel failure

Answer

Software glitch

Answer

Battery swelling

Question 7

A user reports that their smartphone's 3.5mm headphone jack is not working. When headphones are inserted, the music continues to play from the built-in speaker, and the headphone icon does not appear in the status bar. The technician has cleaned the jack with compressed air and tested with multiple headphones. Which of the following components is MOST likely faulty?

Accepted Answer

The headphone jack assembly.. The headphone jack assembly contains a mechanical switch that detects when a plug is inserted and routes audio away from the built-in speaker. Since cleaning and multiple headphones did not resolve the issue, the most likely fault is a broken or stuck detection mechanism within the jack assembly itself, preventing the device from recognizing that headphones are connected.

Answer

The audio codec chip.

Answer

The battery.

Answer

The motherboard.

Question 8

A user reports that their smartphone's GPS cannot get a lock, and the compass app shows a wrong direction. The phone recently had its screen replaced by a third-party repair shop. Which of the following is the MOST likely cause of these issues?

Accepted Answer

The GPS antenna or magnetometer was disconnected or damaged during repair.. The GPS antenna and magnetometer (compass) are often integrated into the display assembly or flex cables near the top of the phone. A third-party screen replacement can easily disconnect or damage these components, causing both GPS lock failure and incorrect compass readings. The digitizer (touch layer) is unrelated to GPS or magnetometer functionality.

Answer

The digitizer is not properly seated.

Answer

The replacement screen's refresh rate is incompatible with the GPS chipset.

Answer

The phone's battery was not calibrated after the screen replacement.

Question 9

A user reports that their smartphone will not power on. The technician connects the phone to a charger and sees a red LED indicator for a few seconds, then it goes off. After leaving it charging for an hour, the phone still will not turn on, and the technician notices the phone feels unusually warm near the battery area. Which of the following components is MOST likely faulty?

Accepted Answer

Battery. The red LED that briefly illuminates and then extinguishes, combined with the phone feeling unusually warm near the battery area after charging, strongly indicates a faulty battery. A degraded or internally shorted battery can accept a small charge (causing the brief red LED) but quickly heat up due to excessive internal resistance or a short circuit, preventing it from holding a charge or powering the device. The battery's inability to deliver sufficient voltage to the system after an hour of charging confirms it is the most likely failed component.

Answer

Charging port

Answer

Screen assembly

Answer

Power button

Question 10

A user dropped their smartphone onto a tile floor. The screen is not cracked and displays images and colors perfectly, but the touch input is completely unresponsive in all areas. The user has rebooted the phone and cleaned the screen. Which of the following hardware components is MOST likely damaged?

Accepted Answer

Digitizer. The digitizer is the layer responsible for converting touch input into electrical signals. Since the display (LCD panel) shows perfect images and colors, the LCD is intact, but the complete lack of touch response indicates the digitizer has been damaged by the drop, likely a cracked or delaminated sensor layer or broken traces.

Answer

LCD panel

Answer

Battery

Answer

Motherboard

Question 11

A user reports that their smartphone will not charge. The phone was working normally until the user plugged it into a generic car charger. Now, when connected to any charger, the phone displays the charging icon but the battery percentage does not increase over time. The technician has tested the phone with a known-good wall charger and cable, and the symptom persists. The phone is detected by a computer and can transfer files over USB. Which of the following components is MOST likely faulty?

Accepted Answer

Power management IC (PMIC). The Power Management IC (PMIC) is the component responsible for regulating the charging voltage and current, and for communicating the battery's charge state to the operating system. Since the phone shows a charging icon (indicating the PMIC is receiving power from the port) but the battery percentage does not increase (indicating the PMIC is not properly charging the battery), and the phone still works normally on USB data (ruling out a full logic board failure), the PMIC is the most likely faulty component. The generic car charger likely sent a voltage spike or improper power signal that damaged the PMIC's charging circuitry.

Answer

Battery

Answer

Charging port

Answer

System board (logic board)

Question 12

A user's Android smartphone recently got a swollen battery and feels warm to the touch even when not in use. The technician checks the battery health using the built-in diagnostic tool, which reports 'Good'. The user mentions the phone was dropped onto a hardwood floor a few days ago. Which of the following is the MOST likely cause?

Accepted Answer

B. The swollen battery and heat generation indicate a physical battery failure, likely caused by internal damage from the drop. The built-in diagnostic tool reports 'Good' because it typically checks electrical parameters (voltage, charge cycles) rather than physical deformation or internal shorts. The drop likely compromised the battery's separator, leading to a thermal runaway risk regardless of software-reported health.

Answer

A

Answer

C

Answer

D

Question 13

A user drops their smartphone onto a concrete floor. The screen displays images and colors correctly, but the touch input is completely unresponsive in all areas. The user has rebooted the phone and cleaned the screen. Which of the following hardware components is MOST likely damaged?

Accepted Answer

Digitizer. The digitizer is the touch-sensitive layer that registers touch input. Since the display shows images and colors correctly but touch is completely unresponsive, the LCD panel and backlight are functioning, isolating the fault to the digitizer. Reboot and cleaning rule out software or surface debris, confirming a hardware digitizer failure.

Answer

LCD panel

Answer

Backlight inverter

Answer

Battery connector

Question 14

A user dropped their smartphone onto a tiled floor. The screen now flickers intermittently and there is a visible column of dead pixels on the left side. The touch input continues to work in the unaffected areas. Which of the following components is MOST likely damaged?

Accepted Answer

LCD panel. The LCD panel is responsible for displaying the image on the screen. A visible column of dead pixels and intermittent flickering, while touch input remains functional in unaffected areas, indicates physical damage to the LCD layer itself. The digitizer (touch layer) is separate and still working, which isolates the fault to the LCD panel.

Answer

Digitizer

Answer

Backlight

Answer

Battery

Question 15

A user's Android smartphone was dropped, causing the glass to shatter. The display still shows images correctly, and touch input works in most areas except for a small region near the top-left corner. The user wants to back up all internal data before taking the phone to a repair shop. Which of the following is the BEST method for the technician to back up the device's data immediately?

Accepted Answer

Use a USB-OTG adapter to connect a mouse. A USB-OTG (On-The-Go) adapter allows the technician to connect a physical mouse to the Android device, providing an alternative input method to navigate the partially broken touchscreen. This enables the user to unlock the phone, access settings, and initiate a backup (e.g., to cloud storage or a connected USB drive) without needing the damaged touch area. It is the fastest and most reliable method when the display is still functional but touch input is compromised in a small region.

Answer

The device cannot be backed up until the screen is replaced

Answer

Use ADB from a computer, assuming USB debugging is already enabled

Answer

Remove the microSD card and copy data via a card reader