Take the tiny bit of carbon dioxide and the tiny bit of water vapor out of the air,
and the rest of what you're breathing right now is a mixture of elements.
Dubnium is a synthetic element ... Number 105. It can be created
in a laboratory but it's not found in nature.
Fifteen (15) different isotopes of Dubnium have been created. They all
have 105 protons in the nucleus of every atom, but they have anywhere
from 256 to 270 neutrons in each nucleus.
The most stable isotope of Dubnium is ²⁶⁸Db , with 163 neutrons in the
nucleus. That form of Dubnium atom has a 50-50 chance of surviving
for around 28 hours before it falls apart.
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Answer:
The actual elevation angle is 12.87 degrees
Explanation:
In the attachment you can clearly see the situation. The angle of elevation as seen for the scuba diver is shown in magenta, we conclude that 
.
Using Snell's Law we can write:
,
Let's approximate the index of refraction of the air (medium 1 in the picture) to 1.
We thus have:
![\implies\theta_1=\arcsin[n_2\sin(\theta_2)]=\arcsin[1.333\sin(47)]\approx 77.13](https://tex.z-dn.net/?f=%5Cimplies%5Ctheta_1%3D%5Carcsin%5Bn_2%5Csin%28%5Ctheta_2%29%5D%3D%5Carcsin%5B1.333%5Csin%2847%29%5D%5Capprox%2077.13)
. Calling 
the actual angle of elevation, we get from the picture that 
