The sun's energy output is a maximum in the visible region of the spectrum. One biological reason we might expect or predict this fact is that
A) it would be impossible for biological photosynthesis to occur if any other region dominated the solar spectrum, and thus plant life could not exist on Earth.
B) the visible region comes right in the middle of the overall electromagnetic spectrum.
C) visible radiation is the only type of solar radiation with enough energy to actually burn our skin.
D) the human eye would be expected to evolve in such a way as to make use of the sun's main energy output.
E) the visible region has the highest frequency.
Question 2
A piece of aluminum with a mass of 1.0 kg and density of 2700 kg/m3 is suspended from a light cord and then completely immersed in a container of water having density 1000 kg/m3.
(a) Determine the volume of the piece of aluminum.
(b) Determine the tension in the cord when the aluminum is immersed in the container of water.
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