Sound intensity of whispering is:
**Core Concept**
The question tests the understanding of sound intensity levels, specifically in the context of human communication like whispering. Sound intensity is measured in decibels (dB), which is a logarithmic unit used to express the ratio of a value of a physical property to a reference value.
**Why the Correct Answer is Right**
Whispering is a form of soft speech, and its sound intensity level is significantly lower than normal conversation. The sound intensity of whispering typically ranges around 20 decibels (dB). This low intensity is due to the reduced airflow and softer vocalization used during whispering, which generates less sound pressure.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because whispering is softer than 40 dB.
**Option B:** This option is incorrect as it exceeds the typical sound level of whispering.
**Option D:** This option is also incorrect because whispering does not reach such high sound levels.
**Clinical Pearl / High-Yield Fact**
It's crucial to remember that sound intensity levels are crucial in diagnosing hearing impairments and in audiometry tests. Whispering is often used as a quick screening tool to assess hearing loss.
**Correct Answer:** Correct Answer: C. 20 dB.