a) These telescopes must make observations above much of the water vapor in the atmosphere because water can block infrared rays.
Explanation:
Ground- based infrared telescopes are placed in a high altitudes dry climates because the telescopes must make observations above much of water vapor since they cut and block them off.
- Telescopes are devices that are used to observe very distant objects.
- An infrared telescope is sensitive to infrared rays.
- Infrared rays are part of the electromagnetic radiations.
- These rays are usually blocked off by the presence of water vapor.
- Desert areas that lacks water vapor in the atmosphere are the most desired for sighting such facilities.
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Answer:
0.625 g
Explanation:
Given data:
Half life of radon-222 = 3.8 days
Total mass of sample = 10 g
Mass left after 15.2 days = ?
Solution:
Number of half lives = T elapsed / Half life
Number of half lives = 15.2 / 3.8
Number of half lives = 4
At time zero = 10 g
At first half life = 10 g/2 = 5 g
At 2nd half life = 5 g/ 2= 2.5 g
At third half life = 2.5 g/2 = 1.25 g
At 4th half life = 1.25 g/2 = 0.625 g
Answer:
The radius of the centrifuge.
Explanation:
Hello,
Since the radius of the centrifuge is just a design parameter, it wouldn't be a cause of failure because it is used to know how many tubes could be fitted in into the centrifuge. On the other hand, keeping you attention away from other factors could turn into a failure as long as the sample could be poured down or just turn out inadequate for the expected results.
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Answer:
Groups
Explanation:
Elements with the same number of valence electrons are found in the same column(group) of the Periodic Table.
Answer:
There are 9.8 ×1021. formula units in 10,005.8gCaO
