What is the intensity of sound in normal conversation?

Correct Option (b) Reason : The word noise is taken from the Latin word nausea and is defined as unwanted or unpleasant sound that causes discomfort.

Intensity of some noise sources is as follows:

Source - Intensity (dB)

Breathing - 10

Broadcasting studio - 20

Trickling clock - 30

Library - 30-35

Normal conversation - 35-60

Telephone - 60

Office noise - 60-80

Alarm clock - 70-80

Traffic - 50-90

Motor cycle - 105

Jet fly (over 1000') - 100-110

Train whistle (50) - 110

Air craft (100) - 110-120

Commercial jet air craft (100) - 120-140

Space rocket (launching) - 170-180