## **Core Concept**
The intensity of sound is measured in decibels (dB) and represents the power of sound per unit area. Normal conversation can be heard from a distance and corresponds to a specific sound intensity level.

## **Why the Correct Answer is Right**
The intensity of normal voice heard from 1 meter is typically around 60 dB. This is because normal conversation between two people usually occurs at a sound intensity level of approximately 60 dB at a distance of 1 meter. This value is a standard reference point in audiology and acoustics.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 30 dB is much too low for normal conversation and corresponds more closely to whispering or quiet environments.
- **Option B:** 80 dB is more characteristic of louder environments such as traffic or a vacuum cleaner and is too high for normal conversation at 1 meter.
- **Option D:** 120 dB is extremely loud, equivalent to the sound of a jet engine, and is far beyond the intensity of normal conversation.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that prolonged exposure to sounds at or above 85 dB can lead to hearing damage. Normal conversation at 1 meter is around 60 dB, which is well below the threshold for hearing damage.

## **Correct Answer:** . 60 dB