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

Decibels (dB) measure power ratios, where a negative value indicates a decrease or loss in power. A fundamental rule to memorize is that every -3 dB change represents cutting the power exactly in half. To go from 12 watts to 3 watts, the power is reduced by a factor of 4 (12 divided by 3 is 4). You can break this down into two steps of cutting the power in half. Cutting the initial 12 watts in half leaves 6 watts, which is a -3 dB change. Cutting that 6 watts in half leaves 3 watts, which is another -3 dB change. Adding these steps together (-3 dB + -3 dB) results in a total power decrease of -6 dB.