Question

The two square faces of a rectangular dielectric slab (dielectric constant 4.0) of dimensions $20cm\times 20cm\times 1.0mm$ are metal-coated. Find the capacitance between the coated surfaces.

Answer 1

$a=20cm\times 20cm=400c{m}^2$

$=4\times {10}^{-2}m,d=1m$

$=1\times {10}^{-3}m,K=4,t=d$

$C=\frac{{\in }_{0}KA}{d}$

$=8.85\times 4\times 4\times 10$

$=141.6\times {10}^{-9}F=1.42nF.$