If the electric flux entering and leaving an enclosed surface is `phi_(1) and phi_(2)` respectively then what is the electric charge inside the surface ?

Explanation

Net electrif flux `(phi)` = Difference of electric flux entering and leaving an enclosed surface.
`rArr " " phi = phi_(2) - phi_(1)`
By Gauss.s theorem `phi = (q)/(epsilon_(0))`
`rArr " " q = phi epsilon_(0)`
`rArr " " q = (phi_(2) - phi_(1)) epsilon_(0)`