Question

A charge q is placed at the centre of the open end of cylindrical vessel. The flux of the electric field through the surface of the vessel is

• A. Zero
• B. $\frac{q}{{ϵ}_0}$
• C. $\frac{q}{2{ϵ}_0}$
• D. $\frac{2q}{{ϵ}_0}$

Answer 1

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

To apply Gauss's theorem it is essential that charge should be placed inside a closed surface. So imagine another similar cylindrical vessel above it. So the flux through the surface will be half the total flux i.e., $\frac{q}{2{ϵ}_0}$