Question

There is an air filled $1 \,pf$ parallel plate capacitor. When the plate separation is doubled and the space is filled with wax, the capacitance increases to $2\,pf$. The dielectric constant of wax is

• A. 2
• B. 4
• C. 6
• D. 8

Answer 1

Answer: (B)

4

Answer 2

$C = \frac{\varepsilon_0 \,A}{d} = 1$ pf and $C' = \frac{k \, \varepsilon_0 \,A}{2d} = 2 \, pf$ This gives k = 4.