Which decibel value most closely represents a power decrease from 12 watts to 3 watts?

الشرح

Dropping from 12 watts to 3 watts is a ratio of 1/4, and 10 × log₁₀(0.25) = −6.02 dB, closest to −6 dB. It can also be seen as two successive halvings, each −3 dB.