The number of technological civilizations in our galaxy is limited by
a. the number of stars in our galaxy
b. the fraction of stars with planets
c. the number of planets per star in habitable zone longer than a few billion years
d. the fraction of suitable planet where technical life forms evolve.
e. All of the above.
E
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Suppose that we increase an N-atom Einstein solid’s value of q = U/? from q to q + 1. By what factor does the value of its multiplicity ? increase? (Choose whichever result is the closest, assuming that q >> 1 and N >> 1.)
A. q B. 3N C. q/3N D. 3N/q E. (q + 3N)/q F. (q +3N)/(qN)
Coulomb's Law: Three point charges are placed on the x-axis, as follows. A charge of +2.0 ?C is at the origin, a charge of -2.0 ?C is at x = 50 cm, and a charge of +4.0 ?C is at x = 100 cm. What are the magnitude and direction of the electrostatic force on the charge at the origin due to the other two charges? (k = 1/4??0 = 9.0 × 109 N ? m2/C2)
What will be an ideal response?
Process of Science: Describe a piece of observational evidence supporting general relativity
What will be an ideal response?
The energy of a photon is ______________ proportional to its wavelength
Fill in the blank(s) with correct word