220-1101 Mobile Devices Practice Question
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?
⚠ Common exam trap
CompTIA often tests the distinction between the digitizer and the LCD panel; the trap here is that candidates see 'touch still works' and assume the screen is fine, but the dead pixel column and flickering point specifically to LCD damage, not the digitizer.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
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 analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Digitizer
Why it's wrong here
The digitizer is the transparent touch-sensitive layer that registers finger contact. Because the display continues to respond to touch in unaffected regions, the digitizer's sensing grid is still functioning. Dead pixels and flickering are visual output defects arising from the display itself, not from touch input detection. A damaged digitizer would cause unresponsive or erratic touch control, not localized pixel damage.
- ✓
LCD panel
Why this is correct
The LCD panel comprises the liquid crystal layer, thin-film transistors, and color filters that generate the image you see. A hard impact can fracture the glass or disturb the liquid crystal alignment, leaving individual sub-pixels permanently off (dead pixels) and creating intermittent electrical connections that cause flickering. These symptoms are textbook for a physically damaged LCD panel, especially after a drop onto a hard floor. Other components remain functional, isolating the fault to the display panel.
- ✗
Backlight
Why it's wrong here
The backlight is the light source, usually LEDs, that shines through the LCD panel. A damaged backlight would produce a dark, dim, or unevenly lit screen, but would not cause specific dead pixels—a dead pixel is a failed liquid crystal cell that blocks or misdirects light, regardless of backlight operation. Flickering that affects only a region could be a backlight issue if it were the whole screen, but here it's confined to the impacted area, pointing to panel damage instead.
- ✗
Battery
Why it's wrong here
The battery provides the device's electrical power, and its failure mode is systemic rather than localized. A damaged battery might cause unexpected shutdowns, inability to charge, or swelling, but it cannot selectively disable individual pixels or induce regional flickering. Pixel-level display anomalies originate in the LCD panel or its driver circuitry, not in the power source. Even if the battery delivered unstable voltage, symptoms would be global (dim screen, random reboots), not pinpoint damage.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1101 exam.