Question

An air filled parallel plate condenser has a capacity of $2\,pF$. The separation of the plates is doubled and the interspace between the plates is filled with wax. If the capacity is increased to $6\,pF$, the dielectric constant of wax is :

• A. 2
• B. 3
• C. 4
• D. 6

Answer 1

Answer: (D)

$C _{\text {old }}=\frac{\varepsilon_{ 0 } A }{ d }=2 pF \rightarrow$ (i)
$C _{\text {new }}=\frac{ K \varepsilon_{ 0 } A }{2 d }=6 pF \rightarrow$ (ii)
By Equating (i) and (ii)
$\frac{ K }{2}(2) pF =6 pF$
$\Rightarrow K =6$