Answer:
decibels (dB)
Explanation:
The sound intensity level is a quantity derived from the sound intensity.
The intensity of a wave is defined as the power of the source of the wave divided by the area through which the power of the wave is spread, mathematically:
where
P is the power of the source
is the surface area over which the wave spreads (assuming that the wave propagates in all directions, it corresponds to the surface area of a sphere of radius 
, where r is the distance between the source of the wave and the observer)
For sound waves, the intensity is often expressed using another unit, called decibel (dB), defined as follows:
where
is the sound intensity level in decibels
I is the intensity of the sound wave
is the threshold intensity of a sound that a person can normally hear.
<span>Vertical lines are 50º apart.
Horizontal lines are 30 minutes apart.</span>
Light will travel more slowly in a material with a higher index of refraction
Answer:
E
Explanation:
Using Coulomb's law equation
Force of the charge = k qQ /d²
and E = F/ q
substitute for F
E = ( K Qq/ d² ) / q
q cancel q
E = KQ / d²
so twice the distance of the from the point charge will lead to the E ( electric field ) decrease by a 4 = E/4. E is inversely proportional to d²
