Lecture 22: Electric Dipole & E Field of Uniform/Non-Uniform Charge Distribution | Dr. Imran Malik

Electric Dipole in an External Electric Field & Numerical Problems | Physics Lecture 22 This lecture continues the study of Electrostatics by exploring the behavior of electric dipoles in external electric fields and solving advanced numerical problems involving electric fields due to both uniform and non-uniform charge distributions. Students will develop a deeper understanding of how electric fields interact with isolated charges and electric dipoles, laying the foundation for potential energy, electric potential, and Gauss's Law. The lecture begins with the derivation and calculation of the electric field due to an electric dipole, followed by step-by-step numerical problems involving both uniformly and non-uniformly distributed charges. Students will learn systematic techniques for calculating the resultant electric field using the principle of superposition and will strengthen their analytical problem-solving skills through examination-oriented examples. A major focus of this lecture is the interaction between charges and external electric fields. Students will first study the force acting on a single point charge placed in a uniform electric field, and then extend the discussion to an electric dipole placed in a uniform external electric field. The lecture demonstrates why the net force on the dipole is zero while a torque acts to align the dipole with the external field. The torque on an electric dipole is derived using the vector approach, while the potential energy of the dipole is derived using the work-energy principle and rotational variables involving torque and the angle θ. Students will understand the relationship between torque and potential energy and see how both the vector description (torque) and the scalar description (potential energy) describe the same physical system because the electrostatic force is a conservative force. This important concept connects mechanics and electrostatics and provides a deeper understanding of energy methods in physics. Throughout the lecture, detailed derivations, conceptual explanations, graphical illustrations, and numerous numerical examples are presented to prepare students for quizzes, assignments, university examinations, and engineering applications. Topics Covered Review of Electric Dipole Electric Field Due to an Electric Dipole Numerical Problems on Electric Fields Uniform Charge Distribution Non-Uniform Charge Distribution Superposition Principle Point Charge in a Uniform Electric Field Force on a Charge in an Electric Field Electric Dipole in a Uniform External Electric Field Net Force on an Electric Dipole Torque on an Electric Dipole Vector Description of Torque Potential Energy of an Electric Dipole Work-Energy Method Rotational Variables (Torque and θ) Conservative Nature of Electrostatic Force Relationship Between Torque and Potential Energy Examination-Oriented Numerical Problems Applications in Science and Engineering Recommended Textbooks Physics for Scientists and Engineers — Raymond A. Serway and John W. Jewett, Jr. University Physics with Modern Physics — Hugh D. Young and Roger A. Freedman Fundamentals of Physics — David Halliday, Robert Resnick, and Jearl Walker This lecture is part of PHY-101 and PHY-102 (Basic Physics) courses for undergraduate students. Keywords Electric Dipole, Electric Dipole Field, Electric Field, Electric Field Numerical Problems, Uniform Charge Distribution, Non-Uniform Charge Distribution, Electric Dipole in Electric Field, Torque on Electric Dipole, Potential Energy of Electric Dipole, Conservative Force, Work-Energy Principle, Superposition Principle, Electrostatics, Engineering Physics, University Physics, Physics Lecture, Basic Physics, Electromagnetism, PHY-101, PHY-102, Physics Tutorial #Physics #ElectricField #ElectricDipole #Electrostatics #Torque #PotentialEnergy #ConservativeForce #EngineeringPhysics #UniversityPhysics #PhysicsLecture #BasicPhysics #Electromagnetism #PHY101 #PHY102 #STEM