350-401 · Question #664
350-401 Question #664: Real Exam Question with Answer & Explanation
The correct answer is A: 13 dBm. Explanation Option A (13 dBm) is correct because in RF power mathematics, every 3 dB increase doubles the transmit power. Starting from 10 dBm, adding 3 dB gives 13 dBm, which represents exactly twice the transmit power (from ~10 mW to ~20 mW). Options B (14 dBm), C (17 dBm), and
Question
If the maximum power level assignment for global TPC 802.11a/n/ac is configured to 10 dBm, which power level effectively doubles the transmit power?
Options
- A13 dBm
- B14 dBm
- C17 dBm
- D20 dBm
Explanation
Explanation
Option A (13 dBm) is correct because in RF power mathematics, every 3 dB increase doubles the transmit power. Starting from 10 dBm, adding 3 dB gives 13 dBm, which represents exactly twice the transmit power (from ~10 mW to ~20 mW).
Options B (14 dBm), C (17 dBm), and D (20 dBm) are incorrect because they do not represent a clean doubling: 14 dBm adds 4 dB (not a standard doubling increment), 17 dBm would represent approximately 5x the original power, and 20 dBm would represent 10x the original power (10 dB = 10× rule).
The two foundational dB rules to remember are:
- +3 dB = double the power
- +10 dB = 10× the power
💡 Memory Tip: Use the phrase "3 dB, double the power; 10 dB, ten times the power" - a classic wireless exam mantra. If you see a question asking about doubling, always look for the answer that is exactly +3 dB above the reference value.
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