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Physics · PYQ NEET UG 2017
हिन्दीSuppose 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 \( m_h = 1.67 \times 10^{-27}\text{ kg} \)]
Correct answer · Option 2
\( 10^{-37}\text{ C} \)
Explanation
Equating electrostatic and gravitational forces between two H atoms: \( \frac{1}{4\pi\varepsilon_0} \frac{(\Delta e)^2}{d^2} = \frac{G m_h^2}{d^2} \implies \Delta e = m_h \sqrt{4\pi\varepsilon_0 G} \approx 10^{-37}\text{ C} \).
