As the universe cooled, it eventually reached a temperature of 3,000 K and protons were able to capture and hold electrons to form neutral hydrogen. This process is known as
a. ionization.
b. isotropy.
c. annihilation.
d. recombination.
e. hydration.
D
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Which of the following makes an approximate uniform electric field?
A) a metal charged sphere B) a metal charged cylinder C) a very long line of positive charge D) very large, closely separated, parallel oppositely charged plates E) two long parallel, closely separated, oppositely charged lines of charge
In a region of space where the electric field is radial, suppose that Er = C/r3, where C is a positive constant. Is the charge density ? in this region positive, negative, or zero? (Note: ? might depend on r in this region.)
A. Positive B. Negative C. Zero D. This is impossible.
Compared to Earth, Venus spins very rapidly on its axis
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