Question

The energy required to charge a parallel plate condenser of plate separation d and plate area of cross-section A such that the uniform electric field between the plates is E is:

Options

• ε₀ E²Ad

• `1/2 ε_0  "E"^2 "Ad"`

• `1/2 ε_0  "E"^2//"Ad"`

• ε₀ E²/Ad

Answer 1

ε₀ E²Ad

Explanation:

Energy required to charge the capacitor is

W = U = QV

⇒ U = CV² = `(ε_0"A")/"d"."V"^2`

= `(ε_0"Ad")/"d"^2."V"^2`

= ε₀ E²Ad ....`[∵ "E" = "V"/"d"]`