Boltzmann/Saha Equation Problems/Questions
March 4, 2011
Boltzmann Equation: Describes how energy levels within atoms are populated.look
at one individual atom, electron may be jumping around but consider atoms as a statistical
ensemble (all at once). The

Boltmann/Saha Equation Examples
March 4, 2011
Boltzmann Equation: Describes how energy levels within atoms are populated.look
at one individual atom, electron may be jumping around but consider atoms as a statistical
ensemble (all at once) and they follow

Ast 228, Problem Set 5 - Solutions
1. Hydrostatic Equilibrium
a) (5 points) The equation of Hydrostatic equilibrium describes the balance between
pressure and gravity. The dierential term represents a pressure gradient as a function of
radius - in other w

Ast 229, Problem Set 2 Solutions
Problem 1: The Bohr Atom
A) Use the Balmer formula (RP eq 5.23 or eq 5.21 in eV) to determine the wavelengths and
the energies of the transitions. Alternatively you can use E=hc/ to determine the energies.
The possible tra

Ast 228, Problem Set 2 Solutions
Feb 23, 2011
Problem 1:
Overall Strategy as discussed in class: Solve this problem by considering the disk to be
composed of thin concentric rings each of mass dM that exerts a force dF on mass m. Set
up the equation for d

Ast 228 Spring 2011, Problem Set 1 Solutions
Problem 1: Consider a body of mass m, moving in a circular orbit, subject to
a central attractive force whose magnitude is given by F(r)=h/r5 , where h is
a constant: a) What are the dimensions of h? b) Derive

Ast 228, Problem Set 7 - Due Wednesday April 27 (If
you want it back before the exam) OR Friday April 29
1. Sizes of Black Holes (4 points)
Although a black hole is by denition a singularity, the size of a black hole can be
characterized by its Schwarzsch

Ast 228 Problem Set 6, Due Friday April 15, 2010
1. Show that the gravitational potential energy of a sphere of radius R, mass M, and constant
mass density is
3 GM 2
U =
5R
Hint: Begin with the general statement for gravitational potential energy for a sh

Ast 228, Problem Set 5 (Stellar Structure)
Due FRIDAY April 8, 2011
1. Hydrostatic Equilibrium The equation of Hydrostatic equilibrium states
GMr (r)
dP
=
dr
r2
a) (5 points) In one paragraph, explain how this dierential equation relates to stellar
struct

Ast 228, Homework 4 - Due Wednesday March 30
1. Find the problems (or parts of problems) from the midterm on which you lost points.
a) State your original answer and write a few sentences describing what you were thinking at the
time and why it was wrong

AST 228 Problem Set 3 - Due Monday March 7*
*Option: Due Friday March 4 if you would like this back before 3/9
1. In class we derived an expression for the energies and wavelengths of atomic transitions using
the Bohr model and quantization of energy (ref

AST 228 Problem Set 2 - Due Wednesday Feb. 23, 2011
1. Consider problem #3 from HW 1/Preclass #2: Calculate the gravitational force that a thin disk
exerts on a point mass m at a distance z along the axis perpendicular to the center of the disk.
Assume a

AST 228 Problem Set 1 - Due Wednesday Feb. 12, 2011
1. Consider a body of mass m, moving in a circular orbit, subject to a central attractive force
whose magnitude is given by F(r)=h/r5 , where h is a constant.
a) What are the dimensions of h?
b) Derive t