This question involves the concepts of Wein's displacement law and characteristic wavelength.
The blackbody temperature will be "3.22 x 10⁵ k".
<h3>WEIN'S DISPLACEMENT LAW</h3>
According to Wein's displacement law,

where,
= characteristic wavelength = 9 μm = 9 x 10⁻⁹ m- T = temperature = ?
- c = Wein's displacment constant = 2.897 x 10⁻³ m.k
Therefore,

T = 3.22 x 10⁵ k
Learn more about characteristic wavelength here:
brainly.com/question/14650107
I would said A is the best option if i’m wrong sorry
Set up a proportion
1 mile/1.6 km = 20,000miles/x
Cross Multiply
x = (20,000) * (1.6)
x = 32,000 kilometers
8.1) Here, Pressure increases with depth in the ocean at higher rate then that of increase in altitude in atmosphere. So, the rate of change of pressure is different in these journeys.So, your most correct answer would be option D.
8.2) Difference in the shape of lines is due to different density of air & water. So, that physical property and your answer would be option A
So, in Short Answers of your questions are:
8.1) - Option D
8.2) - Option A
Hope this helps!