If acoustic power is decreased by -3 dB, which description best matches the change in intensity?

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Multiple Choice

If acoustic power is decreased by -3 dB, which description best matches the change in intensity?

Explanation:
Decibels express ratios of power (or intensity) on a logarithmic scale. A change of -3 dB means the final power is P2 = P1 × 10^(-3/10) ≈ P1 × 0.5, about half of the original. Intensity is power per unit area, and as long as the area stays the same, intensity changes in the same proportion as power. So a -3 dB change in acoustic power corresponds to the intensity being halved. The other options would require different dB changes: +6 dB would quadruple power, -6 dB would quarter it, and +10 dB would increase it tenfold.

Decibels express ratios of power (or intensity) on a logarithmic scale. A change of -3 dB means the final power is P2 = P1 × 10^(-3/10) ≈ P1 × 0.5, about half of the original. Intensity is power per unit area, and as long as the area stays the same, intensity changes in the same proportion as power. So a -3 dB change in acoustic power corresponds to the intensity being halved. The other options would require different dB changes: +6 dB would quadruple power, -6 dB would quarter it, and +10 dB would increase it tenfold.

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