The acceleration of an electron due to the mutual attraction between the electron and a proton when they are \(1.6~\mathring{A}\) apart is:
\(\left(\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9~ \text{Nm}^2 \text{C}^{-2}\right)\)

In the figure, two positive charges \(q_2\) and \(q_3\) fixed along the \(y\)-axis, exert a net electric force in the \(+x\text-\)direction on a charge \(q_1\) fixed along the \(x\)-axis. If a positive charge \(Q\) is added at \((x, 0),\) the force on \(q_1\):

A charged metallic sphere \(A\) is suspended by a nylon thread. Another identical charged metallic sphere \(B\) held by an insulating handle is brought close to \(A\) such that the distance between their centres is \(10\) cm, as shown in Fig.(a). The resulting repulsion of \(A\) is noted. Then spheres \(A\) and \(B\) are touched by identical uncharged spheres \(C\) and \(D\) respectively, as shown in Fig.(b). \(C\) and \(D\) are then removed and \(B\) is brought closer to \(A\) to a distance of \(5.0\) cm between their centres, as shown in Fig. (c). What is the expected repulsion on \(A\) on the basis of Coulomb’s law?

The ratio of the magnitude of electric force to the magnitude of gravitational force for an electron and a proton will be:
(\(m_p=1.67\times10^{-27}~\text{kg}\), \(m_e=9.11\times10^{-31}~\text{kg}\))
1. \(2.4\times10^{39}\)
2. \(2.6\times10^{36}\)
3. \(1.4\times10^{36}\)
4. \(1.6\times10^{39}\)