question_answer

In a parallel plate capacitor the separation between the plates is 3 mm with air between them. Now a 1 mm thick layer of a material of dielectric constant 2 is introduced between the plates due to which the capacity increases. In order to bring its capacity to the original value the separation between the plates must be made

A)  1.5 mm                               

B)  2.5 mm

C)  3.5 mm                               

D)  4.5 mm