Work done by an external agent in separating | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) When a capacitor is disconnected from the battery,the charge $Q$ on its plates remains constant.The capacitance of a parallel plate capacitor is g

Vedclass · Accepted Answer

$\frac{1}{2}CV^2$

Vedclass · Answer

(C) When a capacitor is disconnected from the battery,the charge $Q$ on its plates remains constant.The capacitance of a parallel plate capacitor is given by $C = \frac{\epsilon_0 A}{d}$.As the plates are separated,the distance $d$ increases,so the capacitance $C$ decreases.The energy stored in a capacitor is given by $U = \frac{Q^2}{2C}$.Since $Q$ is constant and $C$ decreases,the energy $U$ increases.The work done by the external agent is equal to the change in the potential energy of the capacitor: $W = \Delta U = U_f - U_i$.If the capacitance changes from $C$ to $C'$,the work done is $W = \frac{Q^2}{2C'} - \frac{Q^2}{2C}$.Given the options provided,the standard expression for energy stored in a capacitor is $\frac{1}{2}CV^2$.

Work done by an external agent in separating the plates of a parallel plate capacitor (disconnected from the battery) is:

Similar Questions

$A$ capacitor has two circular plates,each of radius $8\,cm$,separated by a distance of $1\,mm$. $A$ dielectric slab (dielectric constant $K = 6$) is inserted between the plates. Calculate the energy stored in the capacitor when it is connected to a $150\,V$ potential difference.

An uncharged capacitor is connected to a battery. On charging the capacitor,

The energy stored in the electric field produced by a metal sphere is $4.5\, J$. If the sphere contains $4\,\mu C$ charge,its radius will be.......$mm$. [Take: $\frac{1}{4\pi\varepsilon_0} = 9 \times 10^9\, N\cdot m^2/C^2$]

What is the total energy of the given system in $joules$?

The energy required to charge a parallel plate capacitor with plate separation $d$ and plate area $A$ such that the uniform electric field between the plates is $E$,is

Vedclass Test Series

Exam Paper Generator

Online Exam Module