Two parallel plates have equal and opposite charge. When the space between them is evacuated, the electric field between the plates is \[2\times {{10}^{5}}V/m\]. When the space is filled with dielectric, the electric field becomes\[1\times {{10}^{5}}V/m\]. The dielectric constant of the dielectric material [MP PET 1989]

• A.                    1/2
• B.                                      1
• C.                    2
• D.                                      3