$\begin{aligned}
F_e & =\frac{k q_1 q_2}{r^2} \
F_g & =\frac{G m_1 m_2}{r^2} \
\frac{F_e}{F_g} & =\frac{k q_1 q_2}{G m_1 m_2} \
& =\frac{9 \times 10^9 \times 6.67 \times 10^{-19} \times 9.6 \times 10^{-10}}{6.67 \times 10^{-11} \times 19.2 \times 10^{-27} \times 9 \times 10^{-27}} \
& =\frac{10^{-20}}{2 \times 10^{-65}}
\end{aligned}$
A positive ion A and a negative ion B has charges 6.67 × 10^-19 C and 9.6 × 10^-10 C, and masses 19.2 × 10^-27 ~kg and 9 × 10^-27 ~kg respectively.…
JEE Main 2025 — Physics Electromagnetism
2025integerhard
A positive ion A and a negative ion B has charges 6.67×10−19C and 9.6×10−10C, and masses 19.2×10−27 kg and 9×10−27 kg respectively. At an instant, the ions are separated by a certain distance r. At that instant the ratio of the magnitudes of electrostatic force to gravitational force is P×1045, where the value of 10P is (Take 4πε01=9×109Nm2C−1 and universal gravitational constant as 6.67×10−11Nm2 kg−2 ) Assume that charge may not be an integral multiple of electrons.
Official previous-year question
Held on 23 Jan 2025 · Verified 6 Jul 2026.
Did you get this right?
Sign in to track your attempts and accuracy.
Your note
Sign in to keep a private note on this question. Nothing you write is ever public.
JEE Main Electromagnetism in other years
More JEE Main Electromagnetism questions
$X P Q Y$ is a vertical smooth long loop having a total resistance $R$ where $P X$ is parallel to $Q Y$ and separation between them is $l$. A constant magnetic field $B$ perpendicular to the plane of the loop exists in the entire space. A rod $C D$ of length $L(L>l)$ and mass $m$ is made to slide down from rest under the gravity as shown in figure. The terminal speed acquired by the rod is $\_\_\_\_$ $\mathrm{m} / \mathrm{s}.(\mathrm{g}=$ acceleration due to gravity) 
2026medium
A thin half ring of radius $35$ cm is uniformly charged with a total charge of $Q$ coulomb. If the magnitude of the electric field at centre of the half ring is $100$ V/m, then the value of $Q$ is _______ nC. ($\epsilon_o = 8.85 \times 10^{-12}$ C$^2$/Nm$^2$ and $\pi = 3.14$)
2026medium
A Wheatstone bridge is initially at room temperature and all arms of the bridge have same value of resistances $\left(R_{1}=R_{2}=R_{3}=R_{4}\right)$. When $R_{3}$ resistance is heated to some temperature, its resistance value has gone up by $10 \%$. The potential difference $\left(V_{a}-V_{b}\right)$ (after $R_{3}$ is heated) is $\_\_\_\_$ V. 
2026medium
An inductor of inductance $10$ mH having resistance of $100\,\Omega$ is connected to battery of E.M.F. $1.0$ V through a switch as shown in the figure below. After switch is closed, the ratio of instantaneous voltages across the inductor when the current passing through it is $2$ mA and $4$ mA is _______. 
2026medium
A moving coil of galvanometer when shunted with $2\,\Omega$ resistance gives a full scale deflection for a current of $500$ mA. When a resistance of $470\,\Omega$ is connected in series it gives a full scale deflection for $10$ V potential applied on it. The value of resistance of galvanometer coil is __________ $\Omega$.
2026medium
Other Physics topics for JEE Main
Keep practicing Electromagnetism
Work through every JEE Main Electromagnetism PYQ, year by year.