//example-20.5
//page no-597
//given
//area of plate
A=10*10*10^-6  //m^2
//capacitance
C=10^-9  //F
//distance between the plates
d=2*10^-3  //m
//contant
E0=8.854*10^-12  //F/m
//dielectric constant
Er=C*d/(E0*A)  
printf ("the cielectric constant of the crystal is %f",Er)