Given : mh=1.67×10−27 kg
Net charge on hydrogen atom q=(e+Δe)−e=Δe
Let the distance between them be d.
Equating gravitational force and the electrostatic force, we get
Gm2hd2=k(Δe)2d2
Or (6.67×10−11)(1.67×10−27)2d2=(9×109)(Δe)2d2
⟹ Δe=2.06×10−37 C
The correct answer is option D.