An isolated parallel-plate capacitor of area A1 with an airgap of length s1 is c

Question

An isolated parallel-plate capacitor of area A1 with an airgap of length s1 is charged up to a potential difference V1.A second parallel plate capacitor, initially uncharged, has an areaA2 and a gap of length s2 filled with plastic whose dielectricconstant is K. you connect the wire from the positive plate of thefirst capacitor to one of the plates of the second capacitor, andyou connect another wire from the negative plate of the firstcapacitor to the other late of the second capacitor. what is thefinal potential difference across the first capacitor?

Explanation / Answer

the initial charge on the first cap is   Q = Co Vo . Afterward, the total charge is the same,so     q1 + q2 = Q .    And...     q1 = C1 V1        q2 = C2 V2 .               V1 and V2 are the same because the caps areconnected, so... .                q1 = A1 / s1  V          q2 = K A2 / s2 . So...            A1 / s1   V   +   K A2 / s2   =   ( A1 /s1 )   V1 .             Simplify... .                  V ( A1/s1    +   K A2 /s2)   =   (A1 / s1) V1 . So the final potential difference on both caps is... .       V = V1 (A1 / s1) / (A1/s1   + K A2 / s2 )    which can be written .    V   = V1   A1 s2 / ( A1 s2 + K A2 s1) . So the final potential difference on both caps is... .       V = V1 (A1 / s1) / (A1/s1   + K A2 / s2 )    which can be written .    V   = V1   A1 s2 / ( A1 s2 + K A2 s1)

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.