dB is a standard abbreviation used for the quantitative expression of –
- the dominant Bacillus in a culture
- the density of bacteria in a medium
- a certain pesticide
- a particular pollutant
Answer
(4) a particular pollutant
Solution
dB stands for decibel, the unit of sound intensity level.
As per NCERT, noise is undesired high level of sound; a sound of 150 dB or more (e.g. a jet plane taking off) can damage the ear drums.
∴ dB expresses the level of a particular pollutant — noise.
Answer: (4)