# 8: Maxwell's equations¶

## Example number 8.1, Page number 234¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
K=4.3;     #dielectric constant
c=3*10**8;   #velocity of light in vacuum

#Calculation
n=round(math.sqrt(K),2);    #refractive index of quartz
v=c/n;    #velocity of light in quartz(m/s)

#Result
print "refractive index of quartz is",n
print "velocity of light in quartz is",round(v/10**8,2),"*10**8 m/s"
print "answer for velocity given in the book is wrong"

refractive index of quartz is 2.07
velocity of light in quartz is 1.45 *10**8 m/s
answer for velocity given in the book is wrong


## Example number 8.2, Page number 235¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
epsilon0=8.87*10**-12;   #dielectric permittivity of free space
E=1.2*10**6;     #electric field intensity(N/C)

#Calculation
Ed=(1/2)*epsilon0*(E**2);     #energy density(J/m**2)

#Result
print "energy density is",round(Ed,3),"J/m**2"

energy density is 6.386 J/m**2


## Example number 8.3, Page number 235¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
E0=3*10**6;    #dielectric voltage(V/m)
c=3*10**8;   #velocity of light in vacuum
mew0=4*math.pi*10**-7;

#Calculation
Av=(E0**2)/(2*c*mew0);    #average value of Poynting vector(W/m**2)

#Result
print "average value of Poynting vector is",round(Av/10**11,2),"*10**11 W/m**2"
print "answer given in the book is wrong"

average value of Poynting vector is 0.12 *10**11 W/m**2
answer given in the book is wrong