220-1102 Question 334
Single answerMagnetometersA field technician is troubleshooting a company-issued smartphone used for outdoor navigation. The map app shows the user's location correctly, but the directional arrow spins unpredictably and often points the wrong way even after GPS has locked on. The issue began after the user installed a magnetic folio case. Which action is the MOST appropriate to resolve the problem?
- A
Remove the magnetic case and recalibrate the phone's compass by moving the device in a figure-eight pattern
- B
Disable GPS and reconnect to the mobile carrier so the phone can download new map orientation data
- C
Replace the phone's gyroscope because it is responsible for determining cardinal direction
- D
Clear the map application's cache because corrupted offline map files cause compass drift
Show answer and explanation
Correct answer: A
Explanation
This scenario tests practical knowledge of mobile device sensors in an A+ Core 2 context. The magnetometer is the sensor that detects the Earth's magnetic field and enables compass functionality. When a smartphone shows the correct location but the heading indicator is inaccurate or unstable, a technician should suspect magnetometer interference or calibration problems before replacing hardware. Magnetic accessories, nearby speakers, metal mounts, and some cases can distort readings. Best practice is to remove the interfering accessory, then recalibrate the compass using the device's built-in calibration method. This aligns with standard mobile troubleshooting methodology: identify recent changes, remove the likely cause, and verify normal operation before escalating to component replacement.
- A. Correct.
Correct. A smartphone's magnetometer functions as a digital compass and can be disrupted by nearby magnets or magnetic materials, such as those built into some folio cases. Removing the source of interference and recalibrating the compass is the most appropriate first step. On mobile devices, compass recalibration is commonly performed by moving the phone in a figure-eight motion or following the device vendor's calibration process.
- B. Incorrect.
Incorrect. GPS determines location and can help infer direction while moving, but it is not the primary sensor used for compass heading when a user is standing still or turning in place. Reconnecting to the carrier would not address magnetic interference affecting the magnetometer.
- C. Incorrect.
Incorrect. A gyroscope measures rotational movement and helps with motion tracking and orientation changes, but it does not directly determine magnetic north. A failing gyroscope can affect motion sensing, but the scenario specifically points to incorrect compass direction after adding a magnetic case, which strongly suggests magnetometer interference instead.
- D. Incorrect.
Incorrect. Clearing the map application's cache may resolve issues with stale map data or app performance, but it would not fix a hardware sensor reading that is being distorted by a nearby magnet. The symptom is inaccurate heading, not incorrect map content.