A combination of parallel plate capacitors is maintained at a certain potential difference. When a 3 mm thick slab is introduced between all the plates, in order to maintain the same potential difference, the distance between the plates is increased by 2 . 4 mm . Find the dielectric constant of the slab.

Step-by-step solution

Assume initial separation as 3   mm each capacitance C 1 = ε 0 A 3 before C 1 = k ε 0 A 3 . ε 0 A 2.4 k ε 0 A 3 + ε 0 A 2.4 to get same capacitance ε 0 A 3 = k ε 0 A 3   . ε 0 A 2.4 k ε 0 A 3 + ε 0 A 2.4 3 k = 2.4 k + 3 0.6 k = 3 ⇒ k = 3 0.6 k = 30 6 = 5 .