(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A parallel plate capacitor has a capacitance C when there is a vacuum between teh plates. How does this change if the gap between the plates is half filled with a dielectric with dielectri constant [tex]\epsilon[/tex]_{r}

Calculate the change in energy stored in the capacitor if the dielectric is inserted while the capacitor is connected to a battery of fixed voltage V.

2. Relevant equations

C=C_{1}+C_{2}

C=[tex]\stackrel{\epsilon_0 A}{d}[/tex]

3. The attempt at a solution

For the first part, i assumed it was equivalent to 2 capacitors (one with the dielectric and one without in parallel)

C=[tex]\stackrel{\epsilon_0 0.5A}{d}[/tex] =0.5C

C_{2}= [tex]\epsilon_r[/tex]*[tex]\stackrel{\epsilon_0 0.5A}{d}[/tex] - 0.5[tex]\epsilon_[/tex]C

C(total) = 0.5C+0.5[tex]\epsilon_r[/tex]C.

Second part, not really sure how to start...

V is fixed, and U=0.5CV^{2}.. So if C increases by (1+[tex]\epsilon[/tex]_{r}) U increases by the same factor??

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# Homework Help: Capacitor and dielectriscs

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