220-1101 Mobile Devices Practice Test 10 — 15 Questions

Question 1

A user reports that their laptop's battery indicator shows 'plugged in, not charging.' The technician tests the AC adapter with a multimeter and verifies it outputs the correct voltage. The laptop is a standard model with a removable battery. Which of the following components is MOST likely faulty?

Accepted Answer

Battery. The battery indicator showing 'plugged in, not charging' with a verified good AC adapter strongly points to a faulty battery. Since the adapter outputs correct voltage, the laptop detects the external power source (hence 'plugged in') but the battery itself cannot accept a charge, often due to degraded cells or failed internal protection circuitry. A removable battery is a common failure point, especially in older or heavily used laptops.

Answer

DC power jack

Answer

Motherboard charging circuit

Answer

Power management IC

Question 2

A technician replaced the cracked screen on an iPhone 11. After reassembling the device, the phone powers on and responds to touch, but the display remains black. The technician hears the camera shutter sound when tapping the camera icon. Which of the following is the MOST likely cause?

Accepted Answer

The display cable is not connected properly. The iPhone 11 uses a single display assembly cable that carries both the LCD data and the digitizer (touch) signals. If the display cable is not fully seated or is damaged, the phone may still power on and register touch input (because the digitizer portion of the cable has partial contact), but the LCD backlight or data lines may be interrupted, resulting in a black screen. The camera shutter sound confirms the device is operational and the logic board is functioning, isolating the issue to the display connection.

Answer

The battery connector is loose

Answer

The front camera flex cable is damaged

Answer

The motherboard was damaged during the repair

Question 3

A user reports that their Android smartphone displays 'No SIM card - Emergency calls only' even though the SIM is properly inserted. The technician removes the SIM and inserts it into another compatible phone, where it works perfectly. The technician then inserts a known-working SIM from another phone into the original device, which still shows 'No SIM card.' Which of the following is the MOST likely cause?

Accepted Answer

The SIM slot contacts are damaged or dirty. Since the known-working SIM also fails in the original device, the fault is isolated to the device's SIM interface. Damaged or dirty SIM slot contacts can prevent the electrical connection needed for the phone to detect the SIM, even though the SIM itself is functional. This is the most likely cause because the SIM works in another phone and the original phone fails with any SIM.

Answer

The SIM card tray is upside down

Answer

The IMEI number is corrupted in software

Answer

The phone's baseband firmware needs to be updated

Question 4

A user reports that their smartphone's screen appears to be slightly bulging outward and the back cover is separating from the chassis. The phone still powers on and functions normally. Which of the following components is MOST likely causing this issue?

Accepted Answer

Battery. A bulging screen and separating back cover are classic signs of a swollen lithium-ion battery. As the battery degrades, internal chemical reactions produce gas, causing the battery casing to swell and physically push against the phone's chassis. This occurs even if the phone still powers on and functions normally, as the battery can still deliver voltage while its physical integrity is compromised.

Answer

Digitizer

Answer

LCD panel

Answer

Charging port

Question 5

A user dropped their iPhone, and now the screen displays vertical lines and the touch input is unresponsive in the affected area. The display still shows images and colors correctly in the unaffected areas. Which component is MOST likely damaged?

Accepted Answer

Digitizer. The digitizer is the touch-sensitive layer that detects touch input. When it is damaged, the screen may still display images correctly, but touch input in the affected area becomes unresponsive. The vertical lines are a common symptom of a cracked or damaged digitizer, as the conductive traces that map touch coordinates are broken.

Answer

LCD panel

Answer

Backlight

Answer

Logic board

Question 6

A user reports that their smartphone will not charge when plugged into a wall outlet, even though the charging cable appears undamaged and the outlet works with other devices. Which of the following is the MOST likely cause of this issue?

Accepted Answer

Dirt or lint is blocking the charging port.. The most likely cause is dirt or lint blocking the charging port. When debris accumulates in the port, it can prevent the charging cable from making proper electrical contact with the pins, even though the cable and outlet are functional. This is a common issue with smartphones due to pocket lint or dust, and it typically does not require a battery or system replacement.

Answer

The battery has reached the end of its life and must be replaced.

Answer

The operating system has corrupted system files preventing charging.

Answer

The user is using a charger with insufficient wattage for this phone model.

Question 7

A user reports that their smartphone will not charge when connected to a USB port on their laptop, but it charges fine when plugged into a wall charger. The laptop's other USB ports work with a mouse and keyboard. Which of the following is the MOST likely cause?

Accepted Answer

Laptop USB port power output is too low. The most likely cause is that the laptop's USB port does not provide enough power to charge the smartphone. USB 2.0 ports typically supply up to 500 mA, while many modern smartphones require 1 A or more for charging. The wall charger can supply higher current, which is why charging works there. The fact that the mouse and keyboard work confirms the port is functional for low-power devices.

Answer

Faulty USB cable

Answer

Smartphone's battery is defective

Answer

Laptop USB drivers are outdated

Question 8

A user reports that their smartphone Wi-Fi connection at home frequently drops when they move from one room to another. The home has a single wireless router located in the basement. Which of the following is the MOST likely cause of the intermittent connection?

Accepted Answer

The phone is configured to use only the 5 GHz band.. The 5 GHz band has shorter range and poorer penetration through walls and floors compared to the 2.4 GHz band. When the user moves between rooms, the signal from the basement router may drop below the threshold required for a stable 5 GHz connection, causing intermittent disconnects. The phone being locked to 5 GHz prevents it from falling back to the more robust 2.4 GHz band.

Answer

The phone's Bluetooth is interfering with Wi-Fi.

Answer

The router's firmware is outdated.

Answer

Too many devices are connected to the router.

Question 9

A technician is repairing a smartphone that has a cracked screen. The glass is shattered but the LCD and digitizer underneath are functional except for unresponsive touch in some areas. The user wants all data preserved. After disconnecting the battery, which tool is MOST critical for safely lifting the cracked glass to access the internal components?

Accepted Answer

Suction cup. The suction cup is the most critical tool for safely lifting the shattered glass because it provides a controlled, even pulling force to separate the glass from the frame without further damaging the underlying LCD and digitizer. Since the glass is cracked but the LCD and digitizer are still functional, using a suction cup minimizes the risk of applying uneven pressure that could crack the LCD or tear the digitizer flex cables. This tool is essential for preserving data by avoiding additional damage to the display assembly during disassembly.

Answer

Screwdriver set

Answer

Spudger

Answer

Magnifying glass

Question 10

A user wants to connect their smartphone to an external monitor for a presentation. The monitor only has a VGA input, and the smartphone has a USB-C port that supports DisplayPort Alt Mode. Which cable or adapter should the user obtain to connect the devices?

Accepted Answer

USB-C to VGA adapter. The correct answer is B because the monitor only has a VGA input, which is an analog video interface. The smartphone's USB-C port supports DisplayPort Alt Mode, which can output a digital DisplayPort signal. A USB-C to VGA adapter contains a digital-to-analog converter (DAC) that converts the DisplayPort signal from the phone into an analog VGA signal compatible with the monitor.

Answer

USB-C to HDMI adapter

Answer

USB-C to DisplayPort cable

Answer

Thunderbolt 3 to VGA cable

Question 11

A user's smartphone is connected to a Wi-Fi network but cannot send or receive email. The user can browse the internet using the web browser. Which of the following is the MOST likely cause?

Accepted Answer

The smartphone's date and time settings are incorrect. The smartphone can browse the internet, indicating that the Wi-Fi connection and general internet access are working. Email protocols (IMAP, POP3, SMTP) rely on TLS/SSL certificates for secure connections, and these certificates are validated against the device's system clock. If the date and time are incorrect, the certificate validation fails, preventing the email client from establishing a secure connection to the email server, even though basic web browsing (which may use less strict certificate checks or cached content) still works.

Answer

The email server is offline

Answer

The email account password has changed

Answer

The Wi-Fi signal is weak

Question 12

A technician is replacing the battery in a smartphone. After reassembly, the phone powers on and the screen works, but the battery icon shows 0% charge and the phone does not recognize the battery. The technician verifies that the battery connector is fully seated. Which of the following should the technician check NEXT?

Accepted Answer

The flex cable connecting the battery to the motherboard is damaged. The correct answer is D because the battery connector being fully seated does not rule out damage to the flex cable itself. A damaged flex cable can cause an open circuit or intermittent connection between the battery and the motherboard, preventing the battery management system from reading the battery's charge level or identification data, even though the phone powers on via residual charge or a direct power path.

Answer

The battery is defective and needs to be replaced

Answer

The charging port is damaged

Answer

The battery management chip is faulty

Question 13

A user reports that their smartphone will not power on. When they plug it into a charger, the LED indicator flashes red but the screen remains black. The phone was working normally earlier in the day and was not dropped or exposed to water. Which of the following is the MOST likely cause?

Accepted Answer

Faulty battery. The LED indicator flashing red when the charger is connected, combined with a black screen and no prior physical damage or water exposure, strongly points to a battery that has entered a deep discharge state or has failed. In this scenario, the battery cannot hold enough charge to power the phone's boot sequence, but the charging circuit can still detect the charger and attempt to charge, causing the red LED. A faulty battery is the most common cause of a device that was working normally and then suddenly will not power on, especially when the screen remains black but the LED responds.

Answer

Damaged screen

Answer

Failed CPU

Answer

Corrupted firmware

Question 14

A user reports that their smartphone's battery drains very quickly and the phone feels hot to the touch, even when the phone is idle. The phone is running the latest version of its operating system. Which of the following is the MOST likely cause?

Accepted Answer

A background app using excessive CPU resources. A background app using excessive CPU resources is the most likely cause because high CPU utilization generates significant heat and drains the battery rapidly, even when the phone is idle. The phone's operating system may not effectively throttle such rogue processes, especially if the app is poorly optimized or stuck in a loop. This symptom pattern—heat plus rapid discharge without active use—is classic for a runaway CPU process.

Answer

A faulty charging cable

Answer

A defective battery

Answer

Malware infection

Question 15

A user reports that their smartphone's GPS location is inaccurate, often showing the wrong street or city. The user states that mapping applications open and the phone is able to see satellites, but the blue location dot is far from the actual position. The phone is running the latest operating system version. Which of the following should a technician check FIRST?

Accepted Answer

Date and time settings. Correct answer is B. GPS accuracy heavily depends on precise time synchronization. The GPS satellites broadcast time signals using atomic clocks, and the receiver calculates its position by measuring the time delay of signals from multiple satellites. If the device's date and time settings are incorrect—even by a few seconds—the trilateration calculation will produce an inaccurate position, often showing the wrong street or city. Since the phone can see satellites and open mapping apps, the issue is likely a time offset, not a connectivity or mode problem.

Answer

Location mode setting (e.g., GPS only vs. high accuracy)

Answer

Airplane mode status

Answer

Bluetooth pairing list