A bright red nebula is called an HII region when it contains

A. molecular hydrogen gas, H2.
B. hydrogen atoms which have been ionized by ultraviolet radiation.
C. hydrogen which is generating 21-cm radio waves.
D. hot hydrogen gas thermally glowing.


Answer: B

Physics & Space Science

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The ________ on the edges of the continents come from subduction of oceanic basalt beneath the advancing continental plate

Fill in the blank(s) with correct word

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Determine the energy stored in the 60-?F capacitor



a.
2.4 mJ

b.
3.0 mJ

c.
3.6 mJ

d.
4.3 mJ

e.
6.0 mJ

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Strip mining can be environmentally benign

What will be an ideal response?

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