iran-konkur 2021 Q179

iran-konkur · Other · konkur-riazi_1400_specialized Not Maths
179. Two small conducting spheres with equal and opposite electric charges, $q_1 > 0$ and $|q_2| > q_1$, are held at a fixed distance and an electric force $F$ is exerted on them. If we bring the two spheres into contact and then place them at the same distance, the electric force exerted on them decreases by 20\%. $\left|\dfrac{q_2}{q_1}\right|$ is equal to?
(1) $2$ (2) $4$ (3) $5$ (4) $10$
\textbf{179.} Two small conducting spheres with equal and opposite electric charges, $q_1 > 0$ and $|q_2| > q_1$, are held at a fixed distance and an electric force $F$ is exerted on them. If we bring the two spheres into contact and then place them at the same distance, the electric force exerted on them decreases by 20\%. $\left|\dfrac{q_2}{q_1}\right|$ is equal to?

\begin{center}
(1) $2$ \quad (2) $4$ \quad (3) $5$ \quad (4) $10$
\end{center}