Which of the following statements correctly describes decibels?

The correct statement regarding decibels is that they are logarithmic and relative. Decibels (dB) are a unit of measurement used to express ratios of power or intensity, and they are particularly useful in various fields, including acoustics and sonography. The logarithmic nature of decibels means that a small change in dB represents a substantial change in the actual power or intensity being measured. This allows for a more manageable scale when dealing with large ranges of values, such as sound intensities.

Furthermore, since decibels are relative, they express a comparison between two levels of power or intensity, rather than providing an absolute measurement. This means that in many cases, a reference level is established, and decibel values indicate how much greater or lesser a particular measurement is compared to that reference point. The ability to convey relative differences is particularly important in applications such as evaluating signals in sonography, where variations in amplitude can be critical for proper interpretation.

Understanding decibels in this way is essential for interpreting various measurements effectively, especially in fields such as acoustics and medical imaging.