Question

Consider a hemispherical surface of radius $r$, a positive point charge $q$ is kept at the centre of hemisphere. The electric flux through this hemisphere is :

• A. zero
• B. $\frac{q}{{\epsilon }_0}$
• C. $\frac{q}{2{\epsilon }_0}$
• D. $\frac{2q}{{\epsilon }_0}$

Answer 1

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

if this charge is put at the centre of a sphere then net flux

$=\varphi =q/{\epsilon }_0$ ( hauss s law)

$\Rightarrow$ But this is hemisphere and it contain only half of the field lines and halve flux will become halved

Hence net flux through hemisphere $=\frac{q}{2{\epsilon }_0}$