Which of the following represents the decibel level of rustling of tree leaves in normal circumstances?

Correct answer: (b) 20 dB

Explanation

Sound level is measured in decibels (dB), a logarithmic unit where +10 dB means 10 times more intense sound.

Rustling of tree leaves is about 20 dB; a whisper is around 30 dB and normal conversation about 60 dB.