Question

A point charge $q$ is placed near to an infinitely large plane. Find flux through the plane.

• A. $\frac{q}{{\in }_0}$
• B. $\frac{q}{6{\in }_0}$
• C. $\frac{q}{2{\in }_0}$
• D. $\frac{q}{4{\in }_0}$

Answer 1

The correct option is C $\frac{q}{2{\in }_0}$

As we know if the charge is enclosed in siurface the flux is $\frac{q}{{\epsilon }_0}$. But if it's an infinitely large plate, only the lines going in the plate direction pass through it, which means that only half of the field lines pass through the plate. So if charge is placed near to an infinite plane, then $50\%$ of flux emerging from the point charge will pass through the plane. i.e. $\frac{q}{2{\in }_0}$