220-1101 Mobile Devices Practice Test 3 — 15 Questions

Question 1

A user reports that their iPhone's touchscreen is unresponsive after the device was accidentally dropped in a puddle. The technician dries the phone, performs a forced restart, and cleans the screen, but the touch remains unresponsive. However, the display still shows images correctly. Which component is most likely damaged?

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

Accepted Answer

Digitizer. The digitizer is the component responsible for converting touch input into electrical signals. Since the display still shows images correctly but the touchscreen is unresponsive, the LCD panel and backlight are functioning, isolating the damage to the digitizer layer.

Answer

LCD panel

Answer

Backlight

Answer

Battery

Question 2

A user's Android tablet was dropped and the glass digitizer cracked, but the LCD display still shows images correctly. The user reports that touch input is unresponsive in several areas of the screen. Which of the following replacement procedures is MOST appropriate?

Accepted Answer

Replace the entire screen assembly (LCD and digitizer together). When the glass digitizer is cracked but the LCD display still functions, the digitizer (touch panel) is the damaged component. However, in most modern Android tablets, the digitizer is fused to the LCD as a single screen assembly, making it impractical or impossible to replace only the digitizer without damaging the LCD. Therefore, replacing the entire screen assembly (LCD and digitizer together) is the most appropriate procedure to restore full touch functionality.

Answer

Replace only the LCD display

Answer

Replace only the digitizer (touch panel)

Answer

Perform a touchscreen recalibration

Question 3

A user's smartphone (Android) will not charge via the USB-C port. The technician tries a different cable and charger, and also tries cleaning the port with compressed air. The phone still does not charge. However, the phone can be recognized by a computer when connected via USB. Which of the following should the technician try next?

Accepted Answer

Inspect the port for bent pins.. The phone can still communicate data over USB (recognized by a computer), which proves the power and data lines are partially functional, but a bent pin in the USB-C connector can break the power delivery (PD) negotiation or the VBUS connection required for charging. Cleaning with compressed air only removes debris, not physical damage like bent pins, so a visual inspection is the logical next step.

Answer

Replace the battery.

Answer

Perform a factory reset.

Answer

Update the phone's firmware.

Question 4

A user reports that their Android smartphone displays 'Emergency calls only' at the top of the screen and cannot make or receive regular calls. The device still connects to Wi-Fi and can use messaging apps over Wi-Fi. The technician removes the SIM card, inspects it for damage, and reinserts it. The problem persists. The technician then takes a known-working SIM card from another phone and inserts it into the user's phone; the phone immediately connects to the cellular network. Which of the following is the MOST likely cause?

Accepted Answer

The SIM card is defective or has been deactivated by the carrier.. The technician's swap test with a known-working SIM card immediately restored cellular connectivity, isolating the issue to the original SIM card. Since the phone could still use Wi-Fi and messaging apps, the radio hardware and software stack for cellular were functional, but the SIM card itself was either physically defective or deactivated by the carrier, preventing network registration.

Answer

The phone's cellular antenna is disconnected or damaged.

Answer

The phone is in airplane mode but Wi-Fi is manually re-enabled.

Answer

The mobile network APN settings are incorrectly configured.

Question 5

A user reports that their Android smartphone's battery drains significantly faster than usual. The technician checks the battery usage statistics and finds that the screen is consuming 60% of the battery. The screen brightness is manually set to maximum. Which of the following is the MOST effective step to reduce battery consumption?

Accepted Answer

Reduce screen brightness. The screen is the primary battery consumer, and manual maximum brightness forces the display to use full backlight power. Reducing screen brightness directly lowers the power draw of the display, which is the most effective immediate step to extend battery life. This addresses the root cause identified in the battery usage statistics.

Answer

Disable mobile data

Answer

Remove the battery and reinsert it

Answer

Perform a factory reset

Question 6

A user reports that their Android smartphone will not charge when placed on a wireless charging pad. The phone charges normally when connected via a USB cable. The technician tests the wireless charging pad with another smartphone, and it works fine. Which of the following is the MOST likely cause of the issue?

Accepted Answer

The phone case is interfering with the wireless charging. A thick, metallic, or improperly designed phone case can block or interfere with the electromagnetic field used for inductive charging. Since the charging pad works with another phone and the phone charges via USB, the issue is specific to the phone's ability to receive the wireless signal, and the case is the most common physical barrier.

Answer

The wireless charging coil inside the phone has failed

Answer

The phone is not placed correctly on the charging pad

Answer

A software setting is disabling wireless charging

Question 7

A user's iPhone 11 is stuck in a boot loop after an attempted jailbreak. The device repeatedly shows the Apple logo and then restarts. The technician connects the iPhone to a computer; iTunes displays a message that the device is in recovery mode and must be restored. The technician attempts a force restart and tries a different USB cable and computer, but the iPhone remains in recovery mode and enters the boot loop after any restore attempt. Which of the following is the NEXT best step?

Accepted Answer

Perform a DFU restore. The iPhone is stuck in a boot loop after a failed jailbreak, and standard recovery mode restores are failing. A DFU (Device Firmware Update) restore bypasses the bootloader and iBoot, allowing the device to be completely wiped and the firmware reinstalled at the lowest level, which is necessary to recover from a corrupted boot chain caused by the jailbreak attempt.

Answer

Replace the battery

Answer

Replace the logic board

Answer

Update iOS using over-the-air (OTA)

Question 8

A user reports that their iPhone's battery drains quickly throughout the day. The technician checks the Battery settings and sees that the display is the top consumer at 40%. The user mentions the screen is very bright outdoors. Which of the following settings would MOST effectively reduce battery drain in this scenario?

Accepted Answer

Enable Auto-Brightness.. Enabling Auto-Brightness allows the phone to adjust screen brightness based on ambient light, reducing power consumption when full brightness is not needed. This directly addresses the high display battery usage.

Answer

Turn off Bluetooth.

Answer

Disable Background App Refresh.

Answer

Reduce the screen resolution.

Question 9

A user reports that during phone calls on their Android smartphone, the caller's voice sounds very low and muffled through the earpiece speaker. The technician has cleaned the speaker grille with a soft brush and the issue persists. The phone otherwise functions normally with media sounds playing at adequate volume. Which of the following should the technician check NEXT?

Accepted Answer

Check the call volume setting and adjust it during a test call. The symptom—low and muffled voice specifically during calls, with normal media volume—points to a call volume setting being too low, not a hardware failure. The technician should first adjust the in-call volume during a test call, as this is a separate software-controlled gain stage from media volume. Since cleaning the grille didn't resolve it, the next logical step is to verify and adjust the call volume slider, which is a common user-misconfiguration issue.

Answer

Replace the earpiece speaker module

Answer

Disable Bluetooth to rule out audio redirection

Answer

Reset the audio codec settings in developer options

Question 10

An iPhone 12 charges slowly when connected to a laptop's USB 3.0 port, but charges normally when using the original wall adapter and cable. The technician has already tested the cable with the wall adapter and it works correctly. Which of the following is the MOST likely cause of the slow charging?

Accepted Answer

The laptop's USB port provides lower amperage than the wall adapter. USB 3.0 ports on laptops typically provide a maximum of 0.9A (900mA) of current, while the iPhone 12's original wall adapter can deliver up to 2.4A or more via USB-A to Lightning, or 20W via USB-C Power Delivery. Since the cable works correctly with the wall adapter, the bottleneck is the laptop's USB port's lower amperage, which directly limits charging speed.

Answer

The Lightning cable is damaged

Answer

iOS battery optimization feature is limiting charging speed

Answer

The charging port on the iPhone is damaged

Question 11

A user reports that their Android smartphone can send and receive text messages (SMS) and browse the internet using the cellular data connection, but cannot send picture messages (MMS) to contacts. Which of the following should the technician check FIRST?

Accepted Answer

APN settings. MMS messages require a specific APN configuration that includes both an MMS proxy and MMS port, which are separate from the standard internet APN settings. Since the user can send SMS and browse the web, the core cellular data connection works, but the missing or incorrect MMS proxy/port values in the APN prevent the phone from establishing the necessary WAP gateway connection for MMS delivery. Checking the APN settings first is the logical step because MMS relies on a dedicated data channel through the carrier's MMS server, not the standard internet APN.

Answer

Data roaming setting

Answer

Message center number

Answer

Wi-Fi calling setting

Question 12

A technician needs to replace a cracked LCD screen on an Android smartphone. After disassembling the phone and disconnecting the old screen, which of the following should the technician do FIRST before installing the new screen?

Accepted Answer

Remove or disconnect the battery. The correct first step before installing a new screen is to remove or disconnect the battery. This ensures the device is completely powered off and eliminates the risk of short circuits or electrostatic discharge (ESD) that could damage the new LCD or other sensitive components during installation. Even if the phone appears off, residual charge in capacitors can cause damage if the battery remains connected.

Answer

Connect the new screen and test the display immediately

Answer

Apply adhesive to the frame to secure the new screen

Answer

Update the smartphone's firmware to the latest version

Question 13

A user reports that their Android smartphone charges very slowly when connected to a laptop's USB-C port that supports Power Delivery. The same cable and charger charge the phone quickly when plugged into a wall outlet. The cable is known to be in good condition. Which of the following is the MOST likely cause of the slow charging?

Accepted Answer

The laptop is in battery saving mode, limiting USB power output. When a laptop is in battery saving mode, it often restricts the power output from its USB ports to conserve energy, even if the port supports Power Delivery (PD). This limitation reduces the current available to the smartphone, resulting in slow charging despite the cable and charger being capable of fast charging when connected to a wall outlet.

Answer

The smartphone's USB-C port is damaged

Answer

The cable is not rated for Power Delivery

Answer

The laptop's USB drivers are outdated

Question 14

A user reports that their Android smartphone's touchscreen is unresponsive in a narrow vertical strip near the left edge of the display. The rest of the screen responds normally to touch. The phone has not been dropped or exposed to moisture, and it functions otherwise normally. Which of the following is the MOST likely cause of this issue?

Accepted Answer

Digitizer malfunction. The touchscreen digitizer is the layer responsible for detecting touch input. A narrow vertical strip of unresponsiveness, without any physical damage or other display issues, is a classic symptom of a failing or damaged digitizer, not the LCD panel. The LCD panel only handles image display, which is reported as normal.

Answer

LCD panel damage

Answer

Software calibration issue

Answer

Battery swelling

Question 15

A user reports that their Android smartphone's GPS location often jumps around and shows incorrect positions, especially when indoors. The user has already calibrated the compass and enabled high-accuracy mode. The technician notices the phone has a rugged case with a magnetic kickstand. Which of the following is the MOST likely cause of the GPS inaccuracy?

Accepted Answer

The magnetic kickstand interferes with the magnetometer.. The magnetic kickstand in the rugged case creates a local magnetic field that interferes with the phone's magnetometer. The magnetometer is used to determine the device's orientation relative to Earth's magnetic field, and when it is disrupted, the GPS system cannot accurately correct for heading changes, causing the location to jump or drift, especially indoors where GPS signals are weaker.

Answer

The GPS antenna is damaged.

Answer

The phone's software needs an update.

Answer

The battery is failing and causing voltage fluctuations.