If a charge \( q \) is placed at the centre of a closed hemispherical non-conducting surface, the total flux passing through the flat surface would be:
\( \dfrac{q}{\varepsilon_{0}} \)
\( \dfrac{q}{2 \, \varepsilon_{0}} \)
\( \dfrac{q}{4 \, \varepsilon_{0}} \)
\( \dfrac{q}{2 \pi \varepsilon_{0}} \)