220-1101 Mobile Devices Practice Test 13 — 15 Questions

Question 1

A user drops their smartphone onto a concrete floor. After the fall, the screen displays images and colors correctly, but the touch input does not respond at all. The user has rebooted the phone and wiped the screen clean. Which of the following hardware components is MOST likely damaged?

Accepted Answer

B. The digitizer is the layer of the touchscreen that detects touch input. Since the display (LCD/OLED) still shows images and colors correctly, the digitizer is the most likely component damaged from the drop, as it is a separate, fragile layer bonded to the glass.

Answer

A

Answer

C

Answer

D

Question 2

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 3

A user reports that their Android smartphone's battery drains extremely quickly, and the phone frequently feels warm even when not in use. The technician checks the battery health and it shows 'Good'. The technician notices that the phone's GPS icon appears intermittently in the status bar even when location services are turned off in the settings. Which of the following is the MOST likely cause?

Accepted Answer

A third-party app is requesting location data and keeping the GPS radio active.. The GPS icon appearing intermittently in the status bar, even when location services are disabled in the system settings, strongly indicates that a third-party app is independently requesting location data and keeping the GPS radio active. Android's location service architecture allows apps to request location updates via the Fused Location Provider API, which can bypass the master location toggle if the app has been granted location permissions before the toggle was turned off. This causes the GPS hardware to remain powered on, draining the battery and generating heat, despite the battery health showing 'Good'.

Answer

A malfunctioning battery management IC is overcharging the battery.

Answer

The phone's operating system has a bug that prevents the GPS from turning off.

Answer

The GPS antenna is shorted, causing constant power draw.

Question 4

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 5

A technician is setting up a new Android tablet for a user who wants to connect a Bluetooth keyboard. The keyboard is turned on and in pairing mode. The tablet's Bluetooth is enabled, but the keyboard does not appear in the available devices list. Which of the following should the technician check FIRST?

Accepted Answer

Verify the keyboard's battery is not depleted.. The most common reason a Bluetooth keyboard fails to appear in the device list is that its battery is depleted. Bluetooth keyboards require power to transmit their discovery signals; if the battery is dead, the keyboard cannot broadcast its pairing information, even if it appears to be turned on. The technician should verify the keyboard's battery first because it is the simplest and most likely cause, and it avoids unnecessary troubleshooting steps.

Answer

Ensure the keyboard is within 30 feet (10 meters) of the tablet.

Answer

Check if the tablet's Bluetooth adapter is faulty by testing with another Bluetooth device.

Answer

Restart the tablet to refresh the Bluetooth service.

Question 6

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 7

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 8

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 9

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 10

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 11

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 12

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 13

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. Option A is correct because 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

Question 14

A user drops their smartphone onto a tile floor. The screen is not cracked and the phone powers on normally. However, the phone can no longer detect any Wi-Fi networks, even though other devices in the same location can. Bluetooth continues to work correctly. Which of the following components is MOST likely damaged?

Accepted Answer

The Wi-Fi antenna. The Wi-Fi antenna is a separate physical component from the Bluetooth antenna in many smartphones, even though they often share the same wireless chipset. A drop can break the tiny solder joints or the antenna trace itself, which would prevent the phone from detecting any Wi-Fi networks while leaving Bluetooth functional because Bluetooth uses a different antenna path. Since the phone powers on and the screen is intact, the impact likely damaged only the dedicated Wi-Fi antenna.

Answer

The NFC chip

Answer

The digitizer

Answer

The baseband processor

Question 15

A user's smartphone screen does not auto-rotate when the device is turned sideways. The technician checks the 'Auto-rotate' setting and finds it is enabled. Which of the following components is MOST likely malfunctioning?

Accepted Answer

Gyroscope. The gyroscope is the component responsible for detecting the device's orientation and rotation. When auto-rotate is enabled but the screen does not respond to physical rotation, a malfunctioning gyroscope is the most likely cause, as it provides the angular velocity data needed to trigger the screen orientation change.

Answer

Proximity sensor

Answer

Ambient light sensor

Answer

Magnetometer