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?

Given: The capacitance of the capacitor, C = 600 pF = 600 × 10 - 12 F The supply voltage, V = 200 V The charge on the capacitor, Q = C V = 600 × 10 - 12 × 200 = 12 × 10 - 8 C Therefore, the initial energy in the capacitor, E 1 = Q 2 2 C = 12 × 10 - 8 2 2 × 600 × 10 - 12 = 1 . 2 × 10 - 5 J When the capacitor is connected to the other capacitor of equal capacitance, the charge on the capacitor gets equally distributed on both the capacitors. Hence, the charge on each of the capacitors becomes, Q ' = Q 2 = 12 × 10 - 8 2 = 6 × 10 - 8 C Therefore, the energy in the capacitor is, E 2 = Q ' 2 2 C = 6 × 10 - 8 2 2 × 600 × 10 - 12 = 0 . 3 × 10 - 5 J Both capacitors will have the same energy. The total energy ( E n e t ) is the sum of energies of both the capacitors i.e., E n e t = 2 E 2 = 0 . 6 × 10 - 5 J The loss of energy, E l o s s = E 1 - E n e t = 1 . 2 × 10 - 5 - 0 . 6 × 10 - 5 = 0 . 6 × 10 - 5 J The energy equal to 0 . 6 × 10 - 5 J is lost in the process.

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For a capacitor, the distance between two plates is $5 x$ , the electric field between them is $E_{0}$ , now dielectric slab having dielectric constant $3$ and thickness $x$ is placed between them in contact with one plate. In this condition what is the potential difference between its two plates is:

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Important Questions on Electrostatic Potential and Capacitance

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

The angle between the electric field line and an equipotential surface is _____________.

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Gujarat Board-2018>Q 3

A point $P$ is $40 m$ away from $20 μC$ point charge and $20 m$ from $4 μC$ point charge. The electric potential at point $P$ is____ $V$ .

( $K = 9 \times 10^{9} {Nm}^{2} C^{- 2}$ )

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

For a uniform electric field

\vec{E}

= E_{\circ} (\hat{j})

, if the electric potential at

y = 0

is zero, then the value of electric potential at

y = + y

will be _____.

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

The energy of a charged capacitor is

U

now it is removed from a battery and then is connected to another identical uncharged capacitor in parallel what will be the energy of each capacitor now?

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Gujarat Board-2019>Q 6

For a capacitor the distance between the two plate is

4 x

and the electric field between them is

E_{\circ}

. Now a dielectric slab having dielectric constant

3

and thickness

x

is placed between them in contact with one plate. In this condition what is the p.d. between its two plates?

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Gujarat Board-2019>Q 7

A particle having mass

1 g

and electric charge

10^{- 8} C

travels from a point

A

having electric potential

600 V

to the point

B

having zero potential. What would be the change in its kinetic energy?

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Gujarat Board-2019>Q 9

Derive the formula for the electric potential energy of an electric dipole in a uniform electric field. Discuss its stable and unstable equilibrium state.

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 2 - Electrostatic Potential and Capacitance>Gujarat Board-2020>Q 13

Derive an expression for the capacitance of the parallel plate capacitor.

For a capacitor, the distance between two plates is 5 x, the electric field between them is E0, now dielectric slab having dielectric constant 3 and thickness x is placed between them in contact with one plate. In this condition what is the potential difference between its two plates is:

Important Questions on Electrostatic Potential and Capacitance

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