HW1 Spring 2015 solutions
Problem 1: y factor Make a graph (using excel or similar software) of the relativistic
2
2
factor = (l - y as a function of = -. Use at least 10 values of ranging from 0 up to
v
'
c
0.995. Choose at least half your values to be a

Homework 2
1. Make a table showing the electron's momentum, both the correct relativistic
momentum and the classical values, at speeds with = 0.1, 0.5, 0.9, 0.99.
In the Table below, we show , followed by the classical momentum pCiaSs
22
and the relativis

p.l
Problem I: Charged Particle in an E Field
lt'a positron (or electron antiparticle) beam is accelerated across a potential of 20 kV, find the nal velocity v
of the particles. Do this problem TWICE once using MKS units (J for energy) and a second time u

_l_
5-3.
5.4.
cfw_hl_
i
E eV
^ o-2m'2mc2X2
h
h
=- =
p.mEk
"
(\240eV-nm)
^
/2(5.11105^)(0.04/)2
(from Equation 5-2)
he
yJ2mc2Ek
.
\240eV.nm
(a) For an electron: = -[(2)(0.511xl0 6 eF)(4.5xl0 3 eF)]
= 0.0183wn
.
\240eV >nm
(b)
For a proton: = ; ~
~|"
V
'

Problem 1: a) How many photons are emitted each second from a 5.0 mW HeNe
laser ( = 632.8 nm)? b) If the laser contains 0.02 mole of neon gas, what fraction of the
neon atoms in the tube participate in the lasing process during each second of operation?
,

Chapter 4 - The Nuclear Atom
1
4-1.
=*(\
where R = 1.097 107 m"' (Equation 4-2)
W
2
The Lyman series ends on m =1, the Balmer series on m =2, and the Paschen series on
m =3. The series limits all have = oo, so = 0
f
= 1.097 xl0 7 m"'
=R
l
\
\ J
7
9
,(li