A parallel-plate capacitor of capacitance $5 \mu F$ is connected to a battery of emf $6\; V$. The separation between the plates is $2\; mm$. Choose the right option/s.
(A) the charge on the positive plate is $30 \mu C$
(B) the electric field between the plates is $3 \times 10^3 V/m$
(C) A dielectric slab of thickness 1mm and dielectric constant 5 is inserted into the gap to occupy the lower half of it, then the capacitance of the new combination is $8.3 \; \mu F$
(D) The charge has flown through the battery after the slab is inserted is $20 \mu C$