$A$ medium having dielectric constant $K > 1$ fills the space between the plates of a parallel plate capacitor. The plates have a large area,and the distance between them is $d$. The capacitor is connected to a battery of voltage $V$,as shown in Figure $(a)$. Now,the plates are moved such that the distance between them becomes $2d$,with the dielectric slab of thickness $d$ remaining in between,as shown in Figure $(b)$. In the process of going from the configuration depicted in Figure $(a)$ to that in Figure $(b)$,which of the following statement$(s)$ is(are) correct?

• A
  The electric field inside the dielectric material is reduced by a factor of $2K$.
• B
  The capacitance is decreased by a factor of $\frac{1}{K+1}$.
• C
  The voltage between the capacitor plates is increased by a factor of $(K+1)$.
• D
  The work done in the process $DOES$ $NOT$ depend on the presence of the dielectric material.