Topic: Electric charge, conservation, Coulomb's law, superposition· Electrostatics

Suppose the charge of a proton and an electron differ slightly. One of them is -e, the other is (e+Δ e). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance d (much greater than atomic size) apart…

Suppose the charge of a proton and an electron differ slightly. One of them is \(-e\), the other is \((e+\Delta e)\). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance d (much greater than atomic size) apart is zero, then \(\Delta e\) is of the order of [Given mass of hydrogen \(m_h = 1.67\times10^{-27}\) kg]

1. \(10^{-23}\) C

2. \(10^{-37}\) C

3. \(10^{-47}\) C

4. \(10^{-20}\) C

Doubtly Asked 30 Oct 2026 NEET UG 2017 Practice test neet Save WhatsApp Report

1 answer

Best answer

Answer: 2. \(10^{-37}\) C

Key idea: each hydrogen atom then has a net charge \(\Delta e\), and the electric repulsion balances gravity.

\(\dfrac{(\Delta e)^2}{4\pi\epsilon_0d^2}=\dfrac{Gm_h^2}{d^2}\Rightarrow\Delta e=m_h\sqrt{4\pi\epsilon_0G}\).

\(\Delta e=1.67\times10^{-27}\sqrt{\dfrac{6.67\times10^{-11}}{9\times10^{9}}}=1.67\times10^{-27}\times8.6\times10^{-11}\approx1.4\times10^{-37}\) C.

This is of order \(10^{-37}\) C.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

Was this answer helpful?

Suppose the charge of a proton and an electron differ slightly. One of them is -e, the other is (e+Δ e). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance d (much greater than atomic size) apart…

1 answer

Your answer