Prove that total electrostatic potential energy stored in a capacitor is 1 2 CV 2 . Hence, derive an expression for the energy density of an electric field.

Expression for the stored energy- Suppose a parallel plate capacitor has capacitance.On plats charges are + q and - q and their potential differences is V . ∴ V = q / C . . . . . . . . . . . . ( i ) Now d q charge is transferred than work done. d w = v d q = q / C d q from(i) Now work done in transferring total Q charge. This work is stored in capacitor as potential energy ( U ) . Expression for energy density-

Prove that total electrostatic potential energy stored in a capacitor is 1 2 CV 2 . Hence, derive an expression for the energy density of an electric field.

Expression for the stored energy- Suppose a parallel plate capacitor has capacitance.On plats charges are + q and - q and their potential differences is V . ∴ V = q / C . . . . . . . . . . . . ( i ) Now d q charge is transferred than work done. d w = v d q = q / C d q from(i) Now work done in transferring total Q charge. This work is stored in capacitor as potential energy ( U ) . Expression for energy density-

EASY

12th Nagaland Board

IMPORTANT

Earn 100

A $600 pF$ capacitor is charged by a $200 V$ supply. It is then disconnected from the supply and is connected to another uncharged $600 pF$ capacitor. How much electrostatic energy is lost in the process?

Important Questions on Electrostatic Potential and Capacitance

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Nagaland Board-2018>Q 1

Establish a relationship between electric potential and electric field.

MEDIUM

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Nagaland Board-2018>Q 2

Two point charges of

+ 1.5 μC

and

+ 2.5 μC

are placed

30 cm

apart. Calculate the magnitude of electric potential and electric field at the midpoint of the line joining the two charges.

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Nagaland Board-2019>Q 3

Two charges of

+ 5 nC

and

- 2 nC

are placed at points

(5 cm, 0, 0)

and

(23 cm, 0, 0)

in a region of space where there is no other external electric field. Calculate potential energy of this charge system.

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Nagaland Board-2019>Q 4

Three capacitors are connected as shown in the following figure. Calculate the resultant capacitance. If the combination is connected across a $30 V$ DC battery, find the total charge drawn by the arrangement.

Question Image

HARD

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Nagaland Board-2019>Q 5

Prove that total electrostatic potential energy stored in a capacitor is

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

. Hence, derive an expression for the energy density of an electric field.

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Nagaland Board-2020>Q 6

Derive an expression for electric potential due to a point charge. How do electric potential vary with distance

‘ r ’

for a point charge?

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Nagaland Board-2020>Q 7

A parallel plate capacitor with air between the plates has a capacitance of

8 pF (1 pF = 10^{- 12} F)

. What will be the capacitance of the distance between the plates is reduced by half, and the space between them is filled with a substance of dielectric constant

6

EASY

12th Nagaland Board

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Nagaland Board-2020>Q 8

600 pF

capacitor is charged by a

200 V

supply. It is then disconnected from the supply and is connected to another uncharged

600 pF

capacitor. How much electrostatic energy is lost in the process?

A 600 pF capacitor is charged by a 200V supply. It is then disconnected from the supply and is connected to another uncharged 600pF capacitor. How much electrostatic energy is lost in the process?

Important Questions on Electrostatic Potential and Capacitance

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A $600 pF$ capacitor is charged by a $200 V$ supply. It is then disconnected from the supply and is connected to another uncharged $600 pF$ capacitor. How much electrostatic energy is lost in the process?