Since, hydrogen atom has only one electron in its outermost shell. Thus, the distance between the nucleus and the outer electron will be the Bohr radius.

We know that the columbic force is given by,,where q1 and q2 are the magnitude of charges,r=radius(in this case is Bohr radius)

The value of and the value of Bohr’s radius is r=0.053Å.

The charges of proton and electron are the same but opposite in sign(i.e.).But as we are taking the magnitude of the charges, so we don’t require the sign involved.

Therefore, we obtain the force to be,