Midterm Solutions

# Use the equation of hydrostatic equilibrium dp grr

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Unformatted text preview: = 2π(0.511x106 eV)(0.5 eV)/(1.24 eV µm)2 = 1.04x106 µm ­2 x (106 µm/m)2 = 1.04x1018 m ­2 therefore N+2/N0 = (1.04x1018 m ­2)3/2 e ­(3 eV/0.5 eV) = 2.63x1024 m ­3 We want the fraction N+/N = x, and N+2/N0 = (N+/N)2/[(N ­N+)/N2] = N x2/(1 ­x) = 2.63x1024 m ­3 => x2/(1 ­x) = 5.18x109 based on part (c) Since 0 < x < 1, x must be very close to 1, so we can approximate x = 1 ­(1 ­x) = 1 ­(1 ­[N+/N]) ≈ 1 ­(1/5.18x109) = 1 ­1.9x10 ­10 ≈ 1 Nearly all of the Nubulium is ionized! Page 12 of 16 Physics 160 Fall 2013 Midterm Exam (e) [5 pts] Based on the results from (d), is Prof. Burgasser’s prediction that we would see Nubulium absorption lines in the Solar spectrum a reasonable one? Why or why not? What might be a better type of star to look for this...
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## This document was uploaded on 02/26/2014 for the course PHYS 160 at UCSD.

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