Question

A,B,C,D,E,F are conducting plates each of area A and any two consecutive plates separated by a distance d. The net energy stored in the system after the switch S is closed is:

• A. $\frac{3\varepsilon_{0}A}{2d}$V²
• B. $\frac{5\varepsilon_{0}A}{12d}$V²
• C. $\frac{\varepsilon_{0}A}{2d}$V²
• D. $\frac{\varepsilon_{0}A}{d}$V²

Answer 1

Answer: (C)

$\frac{\varepsilon_{0}A}{2d}$V²

Answer 2

C_eff = since effective capacitance between plates A and E is zero

\ U = $\frac { 1 } { 2 }$ CV² = $\frac { \varepsilon _ { 0 } \mathrm {~A} } { 2 \mathrm {~d} }$V²