//example-20.4
//page no-596
//given
//charge
Q=10*10^-6  //C
//voltage
V=10*10^3  //V
//seperation betweemn the plates
d=5*10^-4  //m
//dielectric eonstant
Er=10
E0=8.854*10^-12
//we know that
//Q=C*V
//so
C=Q/V  //F
//also we know that
//C=Er*E0*A/d
//so
A=C*d/Er/E0  //m^2
printf ("area between the plates is %f m^2",A)