220-1101 Mobile Devices Practice Question
A user reports that their Android smartphone's battery drains very quickly even when the phone is not being used. The technician checks the battery usage statistics and sees that the screen is consuming a high percentage of power, but the screen is off during most of the idle time. Which of the following is the MOST likely cause of this issue?
⚠ Common exam trap
CompTIA often tests the distinction between hardware failure (faulty battery) and software-induced power drain (rogue app), and the trap here is that candidates see 'screen consuming high power' and immediately think brightness or display hardware, ignoring that the screen is off and the power is being misattributed by the OS.
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
✓
A rogue app preventing the phone from sleeping
When the screen is off but still consuming high power in battery statistics, it indicates the device is not entering a proper deep sleep state. A rogue app can hold a partial wake lock (e.g., via Android's PowerManager.WakeLock API) preventing the CPU from suspending, causing the screen subsystem to remain active or the display to be falsely reported as the power consumer. This is the most likely cause because the battery drain occurs during idle periods with the screen physically off.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A faulty battery
Why it's wrong here
A faulty battery typically reduces total capacity or causes erratic charge/discharge behavior, but it does not alter the relative power consumption pattern reported by the battery stats. If a battery were the culprit, the drain would be constant and independent of what components are active, whereas the scenario shows the screen listed as the top consumer while the phone is idle—an impossible hardware-driven outcome. This symptom points to a software wake lock, not a deteriorated cell, so a faulty battery is an incorrect explanation.
When this WOULD be correct
This option would be correct in a scenario where the battery drains quickly under normal usage, the phone gets hot, or the battery swells, and diagnostics show the battery health is degraded or the battery fails a capacity test.
- ✓
A rogue app preventing the phone from sleeping
Why this is correct
A rogue app holding a partial wake lock prevents the Android device from entering deep sleep or Doze mode, keeping the CPU active continuously. Even with the screen off and the phone idle, this background process draws sustained current, causing rapid battery drain that may appear in battery statistics as high 'Screen' or 'System' usage because the device never properly idles. Unlike a brightness issue or hardware fault, this is a software-level condition that directly explains why the phone drains quickly while appearing inactive.
- ✗
The screen brightness set too high
Why it's wrong here
Screen brightness only affects power consumption while the display is actually illuminated. When the phone is idle with the screen off, the backlight and display panel are completely inactive, so the brightness setting has zero influence on idle battery drain. Because the reported symptom is rapid drain even when the phone should be sleeping, a high brightness setting cannot be the cause, as its power contribution is limited to active screen-on usage.
- ✗
Malware infected the phone
Why it's wrong here
While malware can cause battery drain, the specific symptom of the screen being the top power consumer while idle points more directly to a wakelock issue from a legitimate app. Malware is possible but not the most likely cause in this scenario.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 220-1101 exam frequently reuses these exact scenarios with slightly different constraints.
✓A rogue app preventing the phone from sleepingCorrect answer▾
Why this is correct
A rogue app holding a partial wake lock prevents the Android device from entering deep sleep or Doze mode, keeping the CPU active continuously. Even with the screen off and the phone idle, this background process draws sustained current, causing rapid battery drain that may appear in battery statistics as high 'Screen' or 'System' usage because the device never properly idles. Unlike a brightness issue or hardware fault, this is a software-level condition that directly explains why the phone drains quickly while appearing inactive.
✗A faulty batteryWrong answer — click to see why▾
Why this is wrong here
A faulty battery would cause overall poor battery life, but the battery usage statistics show the screen consuming high power while the screen is off, which points to a software issue preventing sleep, not a hardware battery defect.
★ When this WOULD be the correct answer
This option would be correct in a scenario where the battery drains quickly under normal usage, the phone gets hot, or the battery swells, and diagnostics show the battery health is degraded or the battery fails a capacity test.
Why candidates choose this
Candidates may default to blaming the battery for any battery drain issue without analyzing usage statistics, overlooking that the specific symptom (screen power usage while off) indicates a sleep prevention problem.
Analysis generated from the official 220-1101blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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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.