Fast Communication, can be used for good and can be used for bad hackers.
is the intensity of the sound.
Answer: Option B
<u>Explanation:</u>
The range of sound intensity that people can recognize is so large (including 13 magnitude levels). The intensity of the weakest audible noise is called the hearing threshold. (intensity about
). Because it is difficult to imagine numbers in such a large range, it is advisable to use a scale from 0 to 100.
This is the goal of the decibel scale (dB). Because logarithm has the property of recording a large number and returning a small number, the dB scale is based on a logarithmic scale. The scale is defined so that the hearing threshold has intensity level of sound as 0.

Where,
I = Intensity of the sound produced
= Standard Intensity of sound of 60 decibels = 
So for 19 decibels, determine I as follows,



When log goes to other side, express in 10 to the power of that side value,


Everything is in the universe.
That's what the word means.
Answer:
refractive index of the unknown material is 1.33.
Explanation:
μ₁ = 1.21
incidence angle (i) = 41.9°
refraction angle (r) = 37.3°
Let us assume μ be the refractive index of the unknown material
according to snell's law of refraction.
μ₁ sin i = μ₂ sin r
1.21 × sin 41.9° = μ × sin 37.3°
μ = 1.33
hence the refractive index of the unknown material comes out top be 1.33
Answer:
<h2>470.59 kg</h2>
Explanation:
The the mass of the car can be found by using the formula

f is the force
a is the acceleration
From the question we have

We have the final answer as
<h3>470.59 kg</h3>
Hope this helps you