Question

Db is a standard abbreviation used for the quantitative expression of ?

• A. The density of bacteria in a medium.
• B. The dominant Bacillus in a culture.
• C. A certain pesticide
• D. A particular pollutant

Answer 1

The correct option is D

A particular pollutant

The correct option is D.

Explanation for correct option:

1. Db is a standard abbreviation used for the quantitative expression of a noise pollutant.
2. Db stands for Decibel.

Explanation for incorrect options:

Option A:

1. The quantitative measurement of bacteria in a medium is done by optical density at $600$nm ($\mathrm{O}.\mathrm{D}.600$).

Option B:

1. Bacillus culture is measured in terms of colony-forming units (C.F.U.) and transforming units (T.F.U.).

Option C:

1. Pesticides can be measured quantitatively in terms of parts per million (ppm).

Final answer: Db is a standard abbreviation used for the quantitative expression of a particular pollutant.