PHYSICS 112, Sec. 2 S. G. Louie
1st Midterm Exam
FALL 2006 Due: 09/26/06
Note: This is a closed book exam. One sheet of notes (both sides) is allowed. Do all 4 problems. Please display your answers clearly (e.g., in a box) and cross out any work that you
Physics 112, Spring 2010: Holzapfel
Problem Set 2 (6 problems). Due Friday, February 12, 6 PM
Problem 1: Paramagnetism
(a) Kittel, Problem 2.2
(b) Roughly plot the entropy and the temperature as a function of energy. Notice that the temperature is
negativ
Physics 112, Spring 2010: Holzapfel
Problem Set 1 (7 problems). Due Friday, February 5, 4 PM
Problem 1: Sharpness of the multiplicity function.
Suppose you ip 10000 coins. Let P(n) represent the probability that exactly n coins come up heads.
a) What is t
1
The Partition Function: If Thats What It IsWhy Dont They
Say So!
Addison Ault, Cornell College, Mount Vernon, IA 52314
Not long ago a former student was telling me about the Stat Mech course he
had just finished in grad school, and how he had struggled
A Note on Thermal Equilibrium and Multiplicity
Say we have two spin systems S1 and S2 with N1 and N2 particles and energies U1
and U2 , respectively. System S1 with energy U1 has a multiplicity given by a function
g1 (N1 , U1 ) and likewise for S2 . We no
Physics 112 Spring 2010
Professor William Holzapfel
Homework 5 Solutions
Problem 1: Seeing in the dark
(a) Treating the lament as a blackbody, we know that total power is given by Pb = B T 4 A, so the
area is:
100 W
100
=
m2
B T 4
.30 5.67 108 (3500)4
A=
Physics 112 Spring 2010
Professor William Holzapfel
Homework 4 Solutions
Problem 1: Temperature of the Earth and the Greenhouse Eect
(a) We know that at equilibrium, the earth must absorb as much power as it emits: if it absorbed
more, its temperature wou
Physics 112 Fall 2010
Professor William Holzapfel
Homework 3 Solutions
Problem 1: Energy Fluctuations
(a) The easiest way to approach to this problem is probably to start with the right side of
1
the answer. By dening = ,
U
1
U
|V =
|V
|V = 2
U
(1)
Usi
Physics 112 Fall 2007
Professor William Holzapfel
Homework 2 Solutions
Problem 1: Magnetization
a) For the paramagnet, we can use the Gaussian approximation to the multiplicity
in terms of the total number of spins N and the spin excess s:
g (N, s) = g (N
Physics 112 Spring 2010
Professor William Holzapfel
Homework 1 Solution
Problem 1. Sharpness of multiplicity function.
The probability P (n) of getting n heads is the number of congurations that have n heads
divided by the total number of congurations, or
Physics 112, Spring 2010: Holzapfel
Problem Set 6 (6 problems). Due Monday, March 15, 6PM
Problem 1: Centrifuge
Kittel 5.1
Problem 2: Active Transport
Kittel 5.4
Problem 3: Carbon monoxide poisoning
Kittel 5.8
Problem 4: Concentration Fluctuations
Kittel
Physics 112, Spring 2010, Holzapfel
Problem Set 5 (6 problems). Due Friday, March 5th , 6 PM
Problem 1: Seeing in the Dark
Consider a light bulb with a tungsten lament at a temperature of T f = 3500 K.
(a) If the power input is 100 W and the emssivity is
Physics 112, Spring 2010: Holzapfel
Problem Set 4 (6 problems). Due Friday, February 26, 6 PM
Problem 1: Temperature of the Earth & Greenhouse Effect
As seen from the earth, the sun subtends an angle of 1/2 degree. The spectral intensity I of the observed
Physics 112, Spring 2010: Holzapfel
Problem Set 3 (6 problems). Due Friday, February 19, 6 PM
Problem 1: Energy uctuations
(a) Kittel, Problem 3.4
(b) Consider the case of the ideal gas and calculate
become of order 10 percent of the total energy?
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