Question

A parallel plate capacitor has a capacity . The separation between the plates is doubled and a dielectric medium is introduced between the plates. If the capacity now becomes, the dielectric constant of the medium is

• A. 2
• B. 1
• C. 4
• D. 8

Answer 1

Answer: (C)

4

Answer 2

$C _ { 2 } = K \varepsilon _ { 0 } \frac { A } { d _ { 2 } }$

∴ $\frac { C _ { 1 } } { C _ { 2 } } = \frac { 1 } { K } \times \frac { d _ { 2 } } { d _ { 1 } }$ $= \frac { C } { 2 C } = \frac { 1 } { K } \times \frac { 2 d } { d }$ ⇒ K = 4