Question

consider a parallel plate capacitor with value of capacitance C =100(10^-6) F, the plate area,A =0.18m^2 and dielectric constant, εr=7.0

Answer 1

A parallel plate capacitor with a dielectric between its plates has a capacitance given by $C=k \dfrac{A\epsilon_0}{d}$ , where κ is the dielectric constant of the material,$A$ is the area of the plate and $d$ is the distance between the two plates and $\epsilon_0$ is called the permittivity of free space whose value is $8.85*10^{-12}$

putting all the values in the above equation

$\implies100*10^{-6}=7*0.18*8.85*10^{-12}/d$

$\implies d=0.11*10^{-6} m$

$\implies$ $d=0.11{\mu}m$