Q 12-01-027JEE MainJEE Main 2026 (2 Apr, Shift 2)Easy
Two point charges $8\ \mu C$ and $-2\ \mu C$ are located at $x=2$ cm and $x=4$ cm, respectively on the $x$-axis. The ratio of electric flux due to these charges through two spheres of radii $3$ cm and $5$ cm with their centers at the origin is ______.
Answer: (C) $4:3$
By Gauss's law, flux through a closed surface $=\dfrac{q_{enclosed}}{\epsilon_0}$.
Sphere of radius $3$ cm encloses only the $8\ \mu$C charge: $\phi_1=\dfrac{8\ \mu C}{\epsilon_0}$.
Sphere of radius $5$ cm encloses both: $\phi_2=\dfrac{(8-2)\ \mu C}{\epsilon_0}=\dfrac{6\ \mu C}{\epsilon_0}$.
$\phi_1:\phi_2=8:6=4:3$
Solution by Sreeraj P, M.Sc Physics