Course Content
Class 12th Physics Chapter 1 Electric Charges And Fields
NCERT Solutions for Chapter 1 for Class 12 Physics talks about factors and topics related to Electric Charge and Fields. Some of the prominent topics covered in the Chapter are Conductors And Insulators, Charging By Induction, Basic Properties Of Electric Charge, Coulomb’s Law, etc.
Class 12th Physics Chapter 2 Electrostatic Potential And Capacitance
NCERT Solutions for Chapter 2 for Class 12 Physics talks about Electrostatic Potential in detail. The chapter revolves around relevant topics such as Potential Due To A Point Charge, Potential Due To An Electric Dipole, Potential Due To A System Of Charges, Equipotential Surfaces, etc.
Class 12th Physics Chapter 3 Current Electricity
NCERT Solutions for Chapter 3 for Class 12 Physics is an important chapter from weightage point of view. This chapter is very scoring and can be a very interesting chapter for students. The chapter talks about Electric Current, Ohm’s Law, Drift Of Electrons And The Origin Of Resistivity, Limitations Of Ohm’s Law, Resistivity Of Various Materials, etc.
Class 12th Physics Chapter 4 Moving Charges And Magnetism
Chapter 4 for Class 12 Physics can be a very scoring chapter for Class 12 students. However, it is equally complex to understand. It talks about Magnetic Force, Motion In A Magnetic Field, Motion In Combined Electric And Magnetic Fields, etc.
Class 12th Physics Chapter 5 Magnetism And Matter
NCERT Solutions for Chapter 5 for Class 12 Physics talk about topics related to Magnetism and Matter such as the Bar Magnet, Magnetic field lines, The electrostatic analogue, Magnetism And Gauss’s Law, The Earth’s Magnetism, Magnetic declination and dip, Magnetic Properties Of Materials, Diamagnetism, Paramagnetism, Ferromagnetism.
Class 12th Physics Chapter 6 Electromagnetic Induction
A very interesting and Chapter, this one in particular talks about The Experiments Of Faraday And Henry, Magnetic Flux, Faraday’s Law Of Induction, Lenz’s Law and Conservation Of Energy.
Class 12th Physics Chapter 7 Alternating Current
NCERT Solutions for Chapter 7 for Class 12 Physics talk about Ac Voltage Applied To A Resistor, Phasor-diagram solution, Analytical solution, Resonance, Oscillations, and Transformers.
Class 12th Physics Chapter 8 Electromagnetic Waves
In this chapter students will learn about Displacement Current, Electromagnetic Waves, Sources of electromagnetic waves and other such topics related to Electromagnetic Waves.
Class 12th Physics Chapter 9 Ray Optics and Optical Instruments
NCERT Solutions for Chapter 9 for Class 12 Physics talks about Reflection Of Light By Spherical Mirrors, Refraction, Total Internal Reflection and other topics related to Ray Optics.
Class 12th Physics Chapter 10 Wave Optics
NCERT Solutions for Chapter 10 for Class 12 Physics talk about Huygens Principle, Refraction and Reflection Of Plane Waves Using Huygens Principle, Refraction Of A Plane Wave, Refraction At A Rarer Medium etc.
Class 12th Physics Chapter 11 Dual Nature Of Radiation And Matter
Chapter 11 for Class 12 Physics is a scoring chapter. If learnt the concepts thoroughly, it can help students to score high marks in their Physics exam. This chapter talks about Electron Emission, Photoelectric Effect, Hertz’s observations, Hallwachs’ and Lenard’s observations, etc.
Class 12th Physics Chapter 12 Atoms
Chapter 12 for Class 12 Physics is a very interesting yet very confusing chapter for the students. It talks about topics: Alpha-Particle Scattering and Rutherford’s Nuclear Model Of Atom, Alpha-particle trajectory, Electron orbits, Atomic Spectra etc.
Class 12th Physics Chapter 13 Nuclei
NCERT Solutions for Chapter 13 for Class 12 include all answers to the questions included in the textbook. Additionally, the solutions explain topics such as Atomic Masses And Composition Of Nucleus, Size Of The Nucleus, Mass-energy And Nuclear Binding Energy, etc in detail.
Class 12th Physics Chapter 14 Semiconductor Electronics Materials Devices And Simple Circuits
Chapter 14 for Class 12 Physics Is a very scoring and interesting chapter and revolves around topics such as Intrinsic Semiconductor, Extrinsic Semiconductor, P-n Junction, Semiconductor Diode, Application Of Junction Diode As A Rectifier etc.
Class 12th Physics Chapter 15 Communication Systems
NCERT Solutions for Chapter 15 for Class 12 Physics talks about topics related to the communication systems. The important topics are Elements Of A Communication System, Basic Terminology Used In Electronic Communication Systems, etc. This is a very interesting chapter in the Class 12 Physics textbook.
Frequently asked questions (FAQs) Related to Course
Here are some frequently asked questions (FAQs) that could be relevant for your Class 12 Physics Online Course: 1. What is the Class 12 Physics Online Course offered by Free-Education (Wisdom Academy)? Our Class 12 Physics Online Course is a comprehensive learning program designed to help students excel in their CBSE Board exams. It includes chapter-wise notes, important questions, solved and unsolved previous year question papers, video explanations, interactive classes, and more. 2. Who is the instructor for this course? The course is curated and taught by Er. Mohd Sharif, an experienced educator with over 13 years of teaching Physics. He is also the founder of Wisdom Education Academy & Free-Education.In. 3. How can I access the course materials? Once you enroll in the course, you will gain access to our online learning platform. All course materials, including notes, videos, and question papers, can be accessed from there at any time. 4. Are the notes and resources provided in downloadable formats? Yes, our chapter-wise notes and other resources are available in downloadable PDF formats. This allows you to study even when you're offline. 5. How can I ask questions or clear doubts during the course? We offer doubt clearance through online classes, where you can interact with the instructor directly and get your queries resolved. You can also use our platform's messaging system to communicate with the instructor. 6. Are there regular tests to review my preparation? Absolutely, we believe in consistent evaluation. The course includes regular review tests to gauge your understanding and track your progress. 7. Can I access the course on mobile devices? Yes, our online learning platform is mobile-friendly, allowing you to access the course materials on various devices like smartphones and tablets. 8. Are there any prerequisites for enrolling in this course? This course is designed for Class 12 students studying Physics. It's tailored to cover all topics and concepts within the Class 12 Physics curriculum. 9. How can I enroll in the Class 12 Physics Online Course? Enrolling is simple. Visit our website, navigate to the Class 12 Physics Course, and follow the enrollment instructions. 10. Is there a refund policy in case I'm not satisfied with the course? Yes, we have a refund policy in place. If you're not satisfied with the course within the first 7 days, you can request a refund according to our refund policy. 11. Can I interact with other students in the course? Yes, we encourage collaborative learning. Our platform may include discussion forums or other means for students to interact and share insights. 12. Are there any additional resources provided apart from the course materials? In addition to the course materials, we may provide supplementary resources like articles, study tips, and external references to enhance your learning experience. For any other questions or clarifications, feel free to reach out to our support team at (8750387081).
Class 12 Physics Online Course: Notes, Important Questions, and Previous Year Papers
About Lesson


The potential energy of a body is the energy possessed by a body by virtue of its position relative to others, stresses within it, electric charge, and other factors. Examples of mechanical potential energy are throwing a ball in air, a tightened spring etc. Work done in throwing ball and keeping spring tightened gets stored in the form of potential energy which gets converted into kinetic energy once the ball lands on the ground or the spring is released.

Conservative Forces

When one form of energy gets converted to another completely on application or removal of external force, the forces are said to be conservative. Examples of conservative forces are sum of kinetic and potential energies working on a body, spring and gravitational force, coulomb force between two stationary charges, etc.

Electrostatic Potential

Electrostatic potential at a point is the work done by the external force in bringing a charge from infinity to that point.

electrostatic potential
Electrostatic Poltential
Electrostatic Potential and
  • The quantity of potential difference is more physically significant than actual value of potential energy.

WRP = ΔU = UP – UR

(UP +α)-(UR +α) = UP– UR , the arbitrary α has no effect on potential energy difference

If the initial point is at infinity, W∞P = ΔU = UP– U

Uis usually considered as 0, so W∞P = ΔU = UP

electrostatic potential
electrostatic potential

Electrostatic Potential due to a Point Charge

The electrostatic potential in bringing a unit positive test charge from infinity to a point P against repulsive force of another positive charge is always positive.

  • If the charge Q is negative, the potential is also negative as the test charge will have a force of attraction.
  • Electrostatic potential is inversely proportional to r and electrostatic field is inversely proportional to square of r.
Electrostatic potential notes
Electrostatic potential due to point charge
electrostatic potential notes
electrostatic potential

Electrostatic Potential due to an Electric Dipole

An electric dipole is an arrangement of two equal and opposite charges separated by a distance 2a. The dipole moment is represented by p which is a vector quantity.

  • The potential due to a dipole depends on r (distance between the point where potential is calculated and the mid-point of the dipole) and angle between position vector r and dipole moment p.
  • Dipole potential is inversely proportional to square of r.
potential due to an electric dipole
Electric Dipole

Electrostatic Potential due to a system of charges

For a number of charges present in space, the total potential at a point due to all those charges will be equal to the sum of individual potential of each charge at that point.

Potential due to system of charges
electric potential
electrostatic potential
electrostatic potential
electrostatic potential

Equipotential Surfaces

An equipotential surface is one where the potential is same at every point on the surface. For a single charge,

  • Since r is constant, the equipotential surfaces are concentric spherical surfaces centered at the charge.
  • Electric field lines are radial starting from or ending at the charge for positive and negative charges respectively.
electrostatic potential
electrostatic potential

Relation between electric field and potential

According to the relation between electric field and potential,

  • Electric field is in the direction in which the potential decreases steepest.
  • Its magnitude is given by the change in the magnitude of potential per unit displacement normal to the equipotential surface at the point.
electrostatic potential
electrostatic potential

Potential Energy of a system of charges

The potential energy is characteristic of the current state of configuration and not the way how this configuration was achieved.

The potential for a system of charges is calculated as below:

  • Potential energy for the first charge is considered as zero which is brought from infinity to a point having no external repulsive forces (no other charges present in the space).
  • Bringing another charge will face attractive or repulsive force from the first charge and the work done to bring it from infinity to the point is stored in the form of potential energy.
  • Similarly, all further charges being brought from infinity will face attractive or repulsive force from all other charges present in the space.

Potential Energy of point charge in an external field

When the potential energy of charge(s) is calculated in an external field, following things are understood:

  • The electric field, E, is produced by external sources which are fixed and may be unknown.
  • The charge q does not affect these external sources.
  • Potential energy of the external sources is ignored.
Potential Energy of a single charge Potential energy of a system of two charges
qV(rr– position vectorV(r) – external potential at point r q1V(r1) + q2V(r2) + q1q2/(4πε0r12)r1&r2– position vectorsV(r1) & V(r2) – external potential at point r1&r2

Potential Energy of a dipole in an external field

Dipole in an external field experiences a torque which tries to align it in the direction of the electric field. The work done to oppose this force gets stored in the form of potential energy.

electrostatic potential
electrostatic potential
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