SATHEE: electrostatic-potential-and-capacitance Question 18

Electrostatic Potential And Capacitance

electrostatic-potential-and-capacitance Question 18

Question: Q. 1. (i) Write two properties by which electric potential is related to the electric field.

(ii) Two point charges $q_{1}$ and $q_{2}$ , separated by a distance of $r_{12}$ are kept in an external electric field. Derive an expression for the potential energy of the system of two charges in the field.

A [Delhi Compt. I, II, III 2017]

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Solution:

Ans. (i) Properties

(ii) Derivation of expression of potential energy 2

(i) (a) Electric field is in the direction in which potential decreases at the maximum rate.

$1 / 2$

(b) Magnitude of electric field is given by change in the magnitude of potential per unit displacement normal to a charged conducting surface.

(ii) Work done in bringing the charge $q_{1}$ to a point against external electric field

$\begin{matrix} (1) & W_{1} = q_{1} V \vec{r_{1}} \end{matrix}$

Work done in bringing the charge $q_{2}$ against the external electric field and electric field produced due to charge $q_{1}$

$W_{2} = q_{2} V (\vec{r_{2}}) + \frac{1}{4 π ε_{0}} \cdot \frac{q_{1} q_{2}}{r_{12}}$

Therefore, Total work done $=$ Electrostatic potential energy :

$U = q_{1} V (\vec{r_{1}}) + q_{2} V (\vec{r_{2}}) + \frac{1}{4 π ε_{0}} \cdot \frac{q_{1} q_{2}}{r_{12}}$

[CBSE Marking Scheme, 2017]

Electrostatic Potential And Capacitance

electrostatic-potential-and-capacitance Question 18

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Electrostatic Potential And Capacitance

electrostatic-potential-and-capacitance Question 18

Table of Contents

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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