#Variable declaration
r= 5*(10**(-17)) #radius of spherical electron, m
Me= 9.1*(10**(-31)) #mass of electron, kg
h= 6.63*(10**(-34)) #Planck's constant, J.s
#Calculation
import math
hbar= h/(2*(math.pi)) #reduced Planck's constant, J.s
v= (5*math.sqrt(3)/4)*(hbar/(Me*r)) #using Eqn 7.1, Page 230
c= 3*(10**8) #velocity of light, m/s
v= v/c #converting in terms of c, m/s
#Result
print"The velocity of electron in times of c is:%.3g"%v,"c"
#Variable declaration
n= 2 #outer (2s) orbit of lithium
E2= -5.39 #Ionisation energy of lithium, for n=2 eV
E1= -13.6 #for n=1, eV
#Calculation
Z= n*(math.sqrt(E2/E1)) #modification factor for effective charge
e= 1.6*(10**(-19)) #charge of an electron, C
Ceffective = Z*e
#Result
print"The effective charge is: ",round(Ceffective/e,2),"e or%.3g"%Ceffective,"C"
#Variable declaration
n= 2 #for 2p state
Ao= 5.29*(10**(-11)) #Bohr's orbit for n=1, m
r= (n**2)*Ao #orbital radius, m
f= 8.4*(10**14) #frequency of revolution, Hz ,using Eqn 4.4
#Calculation
Mo= 4*(math.pi)*(10**(-7)) #Magnetic constant, T.m/A
e= 1.6*(10**(-19)) #charge of an electron, C
B= (Mo*f*e)/(2*r) #Magnetic field, T
Mb= 9.27*(10**(-24)) #Bohr Magneton, J/T
Um= Mb*B #Magnetic energy, J
Um= Um/e #converting to eV
#Result
print"The magnetic energy for electron is:%.2g"%Um,"eV"
print"\nThe energy difference is twice this,which is:%.2g"%(2*Um),"eV"
#Variable declaration
l= 0.180 #wavelength, nm
l= l* 10**(-9) #converting to m
c= 3*(10**8) #velocity of light, m/s
#Calculation
f= c/l #frequency, Hz
R= 1.097*(10**7) #Rydberg's constant, per m
Z= 1+(math.sqrt((4*f)/(3*c*R))) #using Eqn 7.21
#Result
print"The element has atomic number: ",round(Z)