Question

The electric flux passing through $a$ cube of side $a$ , which holds a charge $q$ at one of its corners is

• A. $\frac{q}{{\epsilon }_0}$
• B. $\frac{q}{8{\epsilon }_0}$
• C. $\frac{q}{4{\epsilon }_0}$
• D. $\frac{q}{2{\epsilon }_0}$

Answer 1

Answer: (B)

Eight identical cubes are required so that the given charge $q$ appears at the centre of the bigger cube
Thus, the electric flux passing through the given cube is
$\varphi =\frac{1}{8}\left(\frac{q}{{\epsilon }_0}\right)$
$=\frac{q}{8{\epsilon }_0}$