Answer
$D = 4.89 \times 10^{-6} C/m^{2}$
Work Step by Step
Given:
Polarization, P, of a dielectric material positioned within a parallel-plate capacitor is to be $4.0 \times 10^{-6} C/m^{2}$, and an electric field of $10^{5}$ V/m is applied.
Required:
dielectric displacement, D
Using Equation 18.31:
$D = ε_{0}E + P = (8.85 \times 10^{-12} F/m)(10^{5} V/m) + (4.0 \times 10^{-6} C/m^{2}) = 4.89 \times 10^{-6} C/m^{2}$