the intensity of the electric field due to proton at a distance of0.2nm is
Electric field at a distance r away from a charged particle with charge Q due to this particle is given by:
E= kQ/(r^2)
In this case,
Q=+1.602 x 10^(-19) Coulombs
r=0.2 X 10^(-9) metres
k=8.99 x 10 9 N m 2 /C 2 .
Putting the values in the equation, we get E=3.600495 x 10^10 N/C .