Answer:
constant velocity unless acted on my an opposite force
Answer:
Metals conduct heat and reduce the kinetic energy within the components that need to remain cool
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.
![\text { Intensity }(d B)=(10 d B) \times \log _{10}\left(\frac{I}{I_{0}}\right)](https://tex.z-dn.net/?f=%5Ctext%20%7B%20Intensity%20%7D%28d%20B%29%3D%2810%20d%20B%29%20%5Ctimes%20%5Clog%20_%7B10%7D%5Cleft%28%5Cfrac%7BI%7D%7BI_%7B0%7D%7D%5Cright%29)
Where,
I = Intensity of the sound produced
= Standard Intensity of sound of 60 decibels = ![1 \times 10^{-12} \mathrm{Wm}^{-2}](https://tex.z-dn.net/?f=1%20%5Ctimes%2010%5E%7B-12%7D%20%5Cmathrm%7BWm%7D%5E%7B-2%7D)
So for 19 decibels, determine I as follows,
![19 d B=(10 d B) \times \log _{10}\left(\frac{I}{1 \times 10^{-12} W m^{-2}}\right)](https://tex.z-dn.net/?f=19%20d%20B%3D%2810%20d%20B%29%20%5Ctimes%20%5Clog%20_%7B10%7D%5Cleft%28%5Cfrac%7BI%7D%7B1%20%5Ctimes%2010%5E%7B-12%7D%20W%20m%5E%7B-2%7D%7D%5Cright%29)
![\log _{10}\left(\frac{1}{1 \times 10^{-12} \mathrm{Wm}^{-2}}\right)=\frac{19}{10}](https://tex.z-dn.net/?f=%5Clog%20_%7B10%7D%5Cleft%28%5Cfrac%7B1%7D%7B1%20%5Ctimes%2010%5E%7B-12%7D%20%5Cmathrm%7BWm%7D%5E%7B-2%7D%7D%5Cright%29%3D%5Cfrac%7B19%7D%7B10%7D)
![\log _{10}\left(\frac{1}{1 \times 10^{-12} \mathrm{Wm}^{-2}}\right)=1.9](https://tex.z-dn.net/?f=%5Clog%20_%7B10%7D%5Cleft%28%5Cfrac%7B1%7D%7B1%20%5Ctimes%2010%5E%7B-12%7D%20%5Cmathrm%7BWm%7D%5E%7B-2%7D%7D%5Cright%29%3D1.9)
When log goes to other side, express in 10 to the power of that side value,
![\left(\frac{I}{1 \times 10^{-12} W m^{-2}}\right)=10^{1.9}](https://tex.z-dn.net/?f=%5Cleft%28%5Cfrac%7BI%7D%7B1%20%5Ctimes%2010%5E%7B-12%7D%20W%20m%5E%7B-2%7D%7D%5Cright%29%3D10%5E%7B1.9%7D)
![I=1 \times 10^{-12} \mathrm{Wm}^{-2} \times 10^{1.9}=1 \times 10^{-12-1.9}=1 \times 10^{-10.1} \mathrm{Wm}^{-2}](https://tex.z-dn.net/?f=I%3D1%20%5Ctimes%2010%5E%7B-12%7D%20%5Cmathrm%7BWm%7D%5E%7B-2%7D%20%5Ctimes%2010%5E%7B1.9%7D%3D1%20%5Ctimes%2010%5E%7B-12-1.9%7D%3D1%20%5Ctimes%2010%5E%7B-10.1%7D%20%5Cmathrm%7BWm%7D%5E%7B-2%7D)
Iron is a magnetic metal, and it is essential to the Earth's magnetic field!
Essentially it "records" (stores the information, maintains) the direction and orientation of the magnetic field.
Among others, the magnetic field protects the Earth from dangerous cosmic rays.
Infrared, visible light, then ultraviolet. Infrared is light that the human eye can not see and visible light is clearly light we can see then ultraviolet is has such a high frequency we can't see it either.