eVidyarthi

Main Menu
  • eVidyarthi
  • School
    • Class 6th
      • Maths Class 6
      • Science Class 6
      • Hindi Class 6
      • व्याकरण
      • English Class 6
      • English Grammar
      • Sanskrit Class 6
      • Geography
      • Civics
      • History
    • Class 7th
      • Maths Class 7
      • Science Class 7
      • Hindi Class 7
      • व्याकरण
      • English Class 7
      • English Grammar
      • Sanskrit Class 7
      • Geography
      • Civics
      • History
    • Class 8th
      • Maths Class 8
      • Science Class 8
      • Hindi Class 8
      • व्याकरण
      • English Class 8
      • English Grammar
      • Sanskrit Class 8
      • Geography
      • Civics
      • History
    • Class 9th
      • Maths Class 9
      • Science Class 9
      • Hindi Class 9
      • English Class 9
      • English Grammar
      • व्याकरण
      • Economics Class 9
      • Geography Class 9
      • Civics Class 9
      • History Class 9
    • Class 10th
      • Maths Class 10
      • Science Class 10
      • Hindi Class 10
      • English Class 10
      • English Grammar
      • व्याकरण
      • Economics Class 10
      • History Class 10
      • Civics Class 10
      • Geography Class 10
    • Class 11th
      • Maths Class 11
      • Accounts Class 11
      • English Class 11
      • English Grammar
      • व्याकरण
      • Chemistry Class 11
      • Physics Class 11
      • Biology Class 11
    • Class 12th
      • Maths Class 12
      • Accounts Class 12
      • Chemistry Class 12
      • Physics Class 12
      • Biology Class 12
      • English Class 12
      • English Grammar
      • व्याकरण
    • Close
  • English
    • Basic English Grammar
    • Basic English Speaking
    • English Vocabulary
    • English Idioms & Phrases
    • Personality Enhancement
    • Interview Skills
    • Close
  • Softwares
    • Microsoft Word
    • PhotoShop
    • Excel
    • Illustrator
    • PowerPoint
    • Close
Class 12th Physics || Menu
  • Important
    • Previous Year Papers
    • Sample Papers
    • MCQs
    • Revision Notes
    • Physics Syllabus
    • Physics Book
    • Marking Scheme
    • Weightage
    • Close
  • Electric Charges and Fields
    • Electric Charge
    • Coulomb’s Law
    • Electric Field
    • Electric Flux
    • Electric Dipole
    • Gauss Law
    • Gold Leaf Electroscope
    • Close
  • Electrostatic Potential and Capacitance
    • Electrostatic Potential
    • Equipotential Surfaces
    • Electrostatic Potential Energy
    • Electrostatics of Conductors
    • Capacitors
    • Combination of Capacitors
    • Electrostatics of Dielectrics
    • Close
  • Current Electricity
    • Ohm’s Law
    • Drift of Electrons and Resistivity
    • Combination of Resistors
    • emfs and Internal Resistance
    • Combination of Cells
    • Kirchhoff’s Rules
    • Electrical Appliances
    • Close
  • Moving Charges and Magnetism
    • Magnetic Lorentz Force
    • Motion in Combined E and B Fields
    • Biot Savart Law
    • Ampere’s Law
    • The Solenoid and Toroid
    • Force on Current Carrying Wire
    • Torque on Current Carrying Loop
    • Close
  • Magnetism and Matter
    • Magnetic Field
    • Magnetic Properties
    • Close
  • Electromagnetic Induction
    • Magnetic Flux
    • Faraday’s Laws of Induction
    • Motional emf
    • Eddy Currents
    • Inductance
    • AC Generator
    • Close
  • Alternating Current
    • AC Applied Across Resistor
    • AC Applied Across Capacitor
    • AC Applied Across Inductor
    • AC Applied to LCR in Series
    • Resonance in LCR Circuit
    • Power in AC Circuit
    • Close
  • Electromagnetic Waves
    • Characteristics of EM Waves
    • Electromagnetic Spectrum
    • Close
  • Ray Optics and Optical instruments
    • Reflection by Spherical Mirrors
    • Refraction by Plane Surfaces
    • Total Internal Reflection
    • Refraction by Spherical Surfaces
    • Refraction by Lens
    • Refraction and Dispersion by Prism
    • Optical Instruments
    • Close
  • Wave Optics
    • Coherent and Incoherent Sources
    • Interference of Light
    • Diffraction of Light
    • Polarisation
    • Close
  • Dual Nature of Radiation and Matter
    • Photoelectric Effect
    • Dual Nature of Matter
    • Close
  • Atoms
    • Alpha Particle Scattering
    • Bohr’s Model of Atom
    • Close
  • Nuclei
    • Atomic Nucleus
    • Nuclear Energy
    • Radioactivity
    • Close
  • Semiconductor Electronics
    • Types of Materials
    • PN Diode
    • Applications of PN Diode
    • Transistors
    • Applications of Transistors
    • Logic Gates
    • Close
  • Communication Systems
    • Signals and Transmission Systems
    • Modulation and Detection of Signals
    • Close

Electrostatic Potential and Capacitance Class 12 Chapter 2 Notes

1. Electrostatic Potential The electrostatic potential at any point in an electric field is equal to the amount of work done per unit positive test charge or in bringing the unit positive test charge from infinite to that point, against the electrostatic force without acceleration.
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-1
NOTE: Electrostatic potential is a state dependent function as electrostatic forces are conservative forces.
2. Electrostatic Potential Difference The electrostatic potential difference between two points in an electric field is defined as the amount of work done in moving a unit positive test charge from one point to the other point against of electrostatic force without any acceleration (i.e. the difference of electrostatic potentials of the two points in the electric field).
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-2
where, is work done in taking charge q0 from A to B against of electrostatic force.
Also, the line integral of electric field from initial position A to final position B along any path is termed as potential difference between two points in an electric field, i.e.
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-3
NOTE: As, work done on a test charge by the electrostatic field due to any given charge configuration is independent of the path, hence potential difference is also same for any path.
For the diagram given as below, potential difference between points A and B will be same for any path.
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-4
3. Electrostatic potential due to a point charge q at any point P lying at a distance r from it is given by
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-5
4. The potential at a point due to a positive charge is positive while due to negative charge, it is negative.
5. When a positive charge is placed in an electric field, it experiences a force which drives it from points of higher potential to the points of lower potential. On the other hand, a negative charge experiences a force driving it from lower potential to higher.
6. Electrostatic potential due to an electric dipole at any point P whose position vector is r w.r.t. mid-point of dipole is given by
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-6
7. The electrostatic potential on the perpendicular bisector due to an electric dipole is zero.
8. Electrostatic potential at any point P due to a system of n point charges q1, q2, ……………, qn whose position vectors are r1,r2,…,rn respectively, is given by
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-7
where, r is the position vector of point P w.r.t. the origin.
9. Electrostatic potential due to a thin charged spherical shell carrying charge q and radius R respectively, at any point P lying
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-8
10. Graphical representation of variation of electric potential due to a charged shell at a distance r from centre of shell is given as below:
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-9
11 Equipotential Surface A surface which have same electrostatic potential at every point on it, is known as equipotential surface.
The shape of equipotential surface due to
(i) line charge is cylindrical.
(ii) point charge is spherical as shown along side:
(a) Equipotential surfaces do not intersect each other as it gives two directions of electric field E at intersecting point which is not possible.
(b) Equipotential surfaces are closely spaced in the region of strong electric field and vice-versa.
(c) Electric field is always normal to equipotential surface at every point of it and directed from one equipotential surface at higher potential to the equipotential surface at lower potential.
(d) Work done in moving a test charge from one point of equipotential surface to other is zero.
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-10
12. Relationship between electric field and potential gradient
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-11
where, negative sign indicates that the direction of electric field is from higher potential to lower potential, i.e. in the direction of decreasing potential.
NOTE: (i) Electric field is in the direction of which the potential decreases steepest.
(ii) Its magnitude is given by the change in the magnitude of potential per unit displacement normal to the equipotential surface at the point.
13. Electrostatic Potential Energy The work done against electrostatic force gets stored as potential energy. This is called electrostatic potential energy.
∆U = UB-UA =WAB
14. The work done in moving a unit positive test charge over a closed path in an electric field is zero. Thus, electrostatic forces are conservative in nature.
15. Electrostatic potential energy of a system of two point charges is given by
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-12
16. Electrostatic potential of a system of n point charges is given by
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-13
17. Potential Energy in an External Field
(i) Potential Energy of a single charge in external field Potential energy of a single charge q at a point with position vector r, in an external field is qV(r),
where V(r) is the potential at the point due to external electric field E.
(ii) Potential Energy of a system of two charges in an external field
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-14
18. Potential energy of a dipole in a uniform electric field E is given by
Potential energy = -p .E
19. Electrostatic Shielding The process which involves the making of a region free from any electric field is known as electrostatic shielding.
electrostatic-potential-and-capacitance-cbse-notes-for-class-12-physics-15
It happens due to the fact that no electric field exist inside a charged hollow conductor. Potential inside a shell is constant. In this way we can also conclude that the field inside the shell (hollow conductor) will be zero.

Android App

eVidyarthi

Search On eVidyarthi

Evidyarthi on Facebook

Like us on Facebook

Follow Evidyarthi on Youtube

Learn English
Learn English Through हिन्दी
Job Interview Skills
English Grammar
हिंदी व्याकरण - Vyakaran
Mathematics Class 6th
Science Class 6th
हिन्दी Class 6th
Mathematics Class 7th
Science Class 7th
हिन्दी Class 7th
हिन्दी Class 8th
Mathematics Class 8th
Mathematics Class 9th
English Class 9th
Science Class 9th
Mathematics Class 10th
English Class 10th
Mathematics Class XI
Chemistry Class XI
Accountancy Class 11th
Accountancy Class 12th
Mathematics Class 12th
Microsoft Word
Microsoft Excel
Microsoft PowerPoint
Adobe PhotoShop
Adobe Illustrator
Learn German
Learn French
IIT JEE
Privacy Policies, Contact Us
Copyright © 2020 eVidyarthi and its licensors. All Rights Reserved.