5. Energy of a Capacitor in the Presence of a Dielectric

[laterrel]

Homework Statement

A dielectric-filled parallel-plate capacitor has plate area of 25.0 cm^2 and plate separation of 9.00 mm. The capacitor is connected to a battery that creates a constant voltage of 7.50 V. The dielectric constant is 2.00. Throughout the problem, use 8.85×10−12 C^2/N \cdot m^2

Homework Equations

U=1/2C*V^2
C=\epsilonA/d
C=K*C_0

The Attempt at a Solution

2.07×10^−10
Keep in mind that the area of each portion of the capacitor is half that of the original capacitor.

 

[member 553083]

C=\epsilonA/dC=(2)(8.85 × 10^−12) (25.0 \ cm^2)/(0.009 \ m)=2.07×10^−10 U=1/2C*V^2U=1/2(2.07×10^−10 )(7.5^2) = 8.59×10^−6 J