Final answer:
The charge density on the plates is -9.0 x 10^-11 C/m².
Step-by-step explanation:
The charge density on the plates can be found by taking the derivative of the electric potential equation with respect to x. In this case, the electric potential equation is V(x) = (8.0 V/m)x + 5.0 V. Taking the derivative, we get dV(x)/dx = 8.0 V/m. The charge density, denoted as σ, is equal to the negative of the derivative of the electric potential, divided by the electric field constant ε₀. Therefore, the charge density on the plates is σ = -8.0 V/m / ε₀.
Using the value of ε₀, which is approximately 8.85 x 10^-12 C²/Nm², we can calculate the charge density. σ = -8.0 V/m / (8.85 x 10^-12 C²/Nm²) = -9.04 x 10^-11 C/m². Finally, expressing the charge density using two significant figures, the charge density on the plates is -9.0 x 10^-11 C/m².