capacitance

Question 1

capacitor

Answer 1

two conductors, isolated from each other and from their surrounding, form a capacitor. The charges on the conductors have the same magnitude q but opposite sign

Question 2

capacitance of the capacitor C =

Answer 2

C = q / V

Question 3

SI unit of capacitance

Answer 3

F(farad)

1 F = 1 C/V

Question 4

How to calculating the Capacitance

parallel-plate capacitor

Answer 4

1) use Gauss’ law to relate q and E
2) integral the E to get the potential different
V = ∫ (-to+) E ds
= E ∫ (0 to d) ds
= E d
3) q = A ε0 V/d
C = q/V = A ε0/d

Question 5

capacitors in parallel

并聯

Answer 5

C = Ca+Cb+….+Cn

Question 6

capacitors in series

Answer 6

1/C = 1/Ca + 1/Cb + …. + 1/Cn