The formula that is applicable here is E = kQ/r^2 in which the energy of attraction is proportional to the charges and inversely proportional to the square of the distance. In this case,
kQ1/(r1)^2 = kQ2/(r2)^2 r1=l/3, r2=2l/3solve Q1/Q2
kQ1/(l/3)^2 = kQ2/(2l/3)^2 kQ1/(l^2/9) = kQ2/(4l^2/9)Q1/Q2 = 1/4
Remember that sound intensity decreases in inverse proportion to the distance squared. So, to solve this we are going to use the inverse square formula:

where

is the intensity at distance 2

is the intensity at distance 1

is distance 2

is distance 1
We can infer for our problem that

,

, and

. Lets replace those values in our formula to find

:





dB
We can conclude that the intensity of the sound when is <span>3 m from the source is
30 dB.</span>
Answer:

Explanation:
= Distance of Andromeda Galaxy from Earth = 
= Time taken = 
= Speed of light = 
We have the relation


The required answer is
.