Technician exam question T5B10
Subelement T5, ELECTRICAL PRINCIPLES· Group T5B
T5B10
Which decibel value most closely represents a power decrease from 12 watts to 3 watts?
- A.-1 dB
- B.-3 dB
- C.-6 dB (correct answer)
- D.-9 dB
WhyA power decrease from 12 watts to 3 watts is most closely represented by -6 dB. Going from 12 watts to 3 watts is a drop to one-quarter of the original power, and since each halving of power is about a 3 dB decrease, two successive halvings, a quarter, works out to roughly -6 dB, answer C. A, B, and D don't correspond to a quartering of power under that same doubling/halving-equals-3-dB rule.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2026-2030 NCVEC Element 2 pool (public domain); the explanation above is original writing, see our methodology.