- Charge CE(k−1) flows through the cell
- The external agent has to do 2 1 E 2 C(k−1) amount of work to take the slab out
After inserting the dielectric the capacitance will be C ′ =kC
The charge flow through the cell when the slab insert is Q ′ =C ′ E=kCE
The charge flow through the cell when the slab is taken out =Q=CE
Net charge flow through the cell Q n =Q ′ −Q=kCE−CE=CE(k−1)
The amount of work for taking out slab is W= 2 1 (CkE2 −CE2)=1/2CE2(k−1)