A parallel plate capacitor has a plate area `3m^(2)`, spaced by 3 dielectric slabs of dielectric constant 2,3,6 and of thickness 0.4mm, 0.6 mm and 1.2mm respectively. Find the effective capacity.

Explanation

Capacity `C=(epsi_(0)Kd)/(d)=(epsi_(0)A)/(d/K)`
Here `C=(epsi_(0)A)/(d_(1)/K_(1)+d_(2)/K_(2)+d_(3)/K_(3))`
`d_(1)=0.4 xx 10^(-3) =4 xx 10^(-4)m, K_(1)=2" "d_(2)=0.6xx 10^(-3)=6 xx 10^(-4)m, K_(2)=3`
`d_(3)=1.2 xx 10^(-3)=12 xx 10^(-4)m, K_(3)=6`
`A=3m^(2)`
`C=(8.854 xx 10^(-12) xx 3)/((4/2+6/3+12/6)xx 10^(-4))=(8.854 xx 10^(-12)xx3)/(6 xx 10^(-4))=4.427 xx 10^(-8)F`