Answer:
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Answer: Δβ (dB) = -13.1dB
Explanation:
The intensity of sound is inversely proportional to the square of the distance between them.
I ∝ 1/r²
I₁/I₂= r₂²/r₁² .....1
When the listener increases his distance from the source by a factor of 4.49.
Then,
r₂/r₁= 4.49
From equation 1
I₁/I₂ = (4.49)²
I₁/I₂ = 20.16
I₂/I₁ = 1/20.16
The change in sound intensity in dB can be given as
Δβ (dB) = 10 log(I₂/l₁) = 10log(1/20.6) = -13.1dB
Answer:
A
Explanation:
You did not list the options. However, knowing the possible options from having seen the material myself - I can infer that the answer option is A. I apologize sincerely if this is wrong.
The answer is B. because NaCl are just two elements with one atom from each element
The formula for aluminium chloride will be correctly written as AlCl3.
Aluminium is a metal and in this reaction it is an electron donor. It has three electrons in its outermost shell and it is ready to give out all the three electrons to chlorine. Chlorine is a non metal and is an electron acceptor and it is more than ready to accept electrons from aluminium. But a chlorine atom can only receive only one electron from aluminium because, it already has seven electrons in its outermost shell and it only needs eight electrons in its outermost shell to be stable. To solve this problem, three chlorine atoms will react with one aluminium atom in order to accept all the three electrons from aluminium, hence the chemical formula AlCl3..
