Topics
Electric Charges and Fields
- Electric Charge
- Electrical Conduction in Solids
- Principle of Superposition
- Electric Field
- Electric Field Due to a System of Charges
- Physical Significance of Electric Field
- Electric Lines of Force
- Electric Flux
- Electric Dipole
- Dipole in a Uniform External Field
- Continuous Charge Distribution
- Gauss’s Law
- Applications of Gauss' Theorem
- Charging by Induction
- Electric Field Intensity Due to a Point-Charge
- Uniformly Charged Infinite Plane Sheet and Uniformly Charged Thin Spherical Shell (Field Inside and Outside)
- Overview: Gauss' Theorem
- Conductors and Insulators
- Important Properties of Electric Charge
- Scalar Form of Coulomb’s Law
- Electric Field due to an Electric Dipole
Electrostatics
Current Electricity
Electrostatic Potential and Capacitance
- Electric Potential
- Potential Due to a Point Charge
- Potential Due to an Electric Dipole
- Potential Due to a System of Charges
- Equipotential Surfaces
- Relation Between Electric Field and Electrostatic Potential
- Potential Energy of a System of Charges
- Potential Energy of a Single Charge
- Potential Energy of a System of Two Charges in an External Field
- Potential Energy of a Dipole in an External Field
- Electrostatics of Conductors
- Dielectrics
- Capacitors and Capacitance
- The Parallel Plate Capacitor
- Effect of Dielectric on Capacity
- Combination of Capacitors
- Energy Stored in a Charged Capacitor
- Van De Graaff Generator
- Capacitance of a Parallel Plate Capacitor with and Without Dielectric Medium Between the Plates
- Free Charges and Bound Charges Inside a Conductor
- Conductors and Insulators Related to Electric Field
- Electrical Potential Energy of a System of Two Point Charges and of Electric Dipole in an Electrostatic Field
- Potential and Potential Difference
- Overview: Electric Potential
- Overview: Capacitors and Dielectrics
Magnetic Effects of Current and Magnetism
Current Electricity
- Electric Current
- Concept of Electric Currents in Conductors
- Ohm's Law
- Current Density
- Drift of Electrons and the Origin of Resistivity
- Limitations of Ohm’s Law
- Resistivity of Various Materials
- Temperature Dependence of Resistance
- Electrical Power
- Cells, Emf, Internal Resistance
- Cells in Series
- Kirchhoff’s Laws
- Wheatstone Bridge
- Conductivity and Conductance;
- Delta Star Transformation
- Potential Difference and Emf of a Cell
- Measurement of Internal Resistance of a Cell
- Potentiometer
- Metre Bridge: Slide-Wire Bridge
- A combination of resistors in both series and parallel
- Specific Resistance
- V-I Characteristics (Linear and Non-linear)
- Flow of Electric Charges in a Metallic Conductor
- Overview: Electric Resistance and Ohm's Law
- Overview: DC Circuits and Measurements
Electromagnetic Induction and Alternating Currents
Moving Charges and Magnetism
- Magnetic force
- Sources and Fields of Magnetic Force
- Magnetic Field, Lorentz Force
- Force on a Current Carrying Conductor in a Magnetic Field
- Motion in a Magnetic Field
- Biot-Savart Law
- Magnetic Field on the Axis of a Circular Current Loop
- Ampere’s Circuital Law
- Solenoid and the Toroid - the Solenoid
- Force Between Two Parallel Currents, the Ampere
- Circular Current Loop as a Magnetic Dipole
- Torque on a Rectangular Current Loop in a Uniform Magnetic Field
- Moving Coil Galvanometer
- Oersted's Experiment
- Solenoid and the Toroid - the Toroid
- Magnetic Diapole
- Torque on a Current-Loop in a Uniform Magnetic Field
- Force on a Current - Carrying Conductor in a Uniform Magnetic Field
- Force on a Moving Charge in Uniform Magnetic and Electric Fields
- Straight and Toroidal Solenoids (Only Qualitative Treatment)
- The Magnetic Dipole Moment of a Revolving Electron
- Velocity Selector
- Cyclotron
- Overview: Moving Charges and Magnetic Field
- Overview: Torque on a Current-Loop : Moving-Coil Galvanometer
Electromagnetic Waves
Magnetism and Matter
- Concept of Magnetism
- The Bar Magnet
- Magnetism and Gauss’s Law
- Magnetisation and Magnetic Intensity
- Magnetic Properties of Materials
- Permanent Magnet
- Curie Law of Magnetism
- Hysteresis: Retentivity and Coercivity
- The Earth’s Magnetism
- Torque on a Magnetic Dipole (Bar Magnet) in a Uniform Magnetic Field
- Dipole in a Uniform External Field
- Magnetic Field Intensity Due to a Magnetic Dipole (Bar Magnet) Perpendicular to Its Axis
- Magnetic Field due to a Bar Magnet
- Magnetic Dipole Moment of a Revolving Electron
- Current Loop as a Magnetic Dipole: Magnetic Dipole Moment of Current Loop
- Magnetic Substances
- Overview: Magnetism and Mater
Optics
Electromagnetic Induction
- Electromagnetic Induction
- The Experiments of Faraday and Henry
- Magnetic Flux
- Faraday's Laws of Electromagnetic Induction
- Lenz’s Law and Conservation of Energy
- Motional Electromotive Force (e.m.f.)
- Mutual Inductance
- Self Inductance
- A.C. Generator
- Energy Consideration: a Quantitative Study
- Eddy Currents or Foucault Currents
- Induced Current and Induced Charge
- Overview - Electromagnetic Induction
Dual Nature of Radiation and Matter
Alternating Current
- Alternating current (AC) and Direct Current (DC)
- Different Types of AC Circuits: AC Voltage Applied to a Resistor
- Representation of AC Current and Voltage by Rotating Vectors - Phasors
- Different Types of AC Circuits: AC Voltage Applied to an Inductor
- Different Types of AC Circuits: AC Voltage Applied to a Capacitor
- Different Types of AC Circuits: AC Voltage Applied to a Series LCR Circuit
- Power in AC Circuit
- Forced Oscillations and Resonance
- Transformers
- LC Oscillations
- Reactance and Impedance
- Peak and Rms Value of Alternating Current Or Voltage
- Overview: AC Circuits
Atoms and Nuclei
Electromagnetic Waves
- Elementary Facts About Electromagnetic Wave Uses
- Electromagnetic Spectrum
- Transverse Nature of Electromagnetic Waves
- EM Wave
- Displacement Current
- Overview of Electromagnetic Waves
Ray Optics and Optical Instruments
- Reflection of Light by Spherical Mirrors
- Refraction of Light
- Refraction at a Spherical Surface and Lenses
- Refraction by a Lens
- Refraction at Spherical Surfaces
- Power of a Lens
- Refraction of Light Through a Prism
- Optical Instruments
- Simple Microscope or a Reading Glass
- Compound Microscope
- Telescope
- Optical Instruments: the Eye
- Laws of Refraction
- Spherical Mirror > Concave Mirror
- Rarer and Denser Medium
- Lens Maker's Formula
- Thin Lens Formula
- Concept of Lenses
- Some Natural Phenomena Due to Sunlight
- Dispersion by a Prism
- Magnification
- Total Internal Reflection
- Ray Optics - Mirror Formula
- Overview of Ray Optics and Optical Instruments
- Light Process and Photometry
Electronic Devices
Wave Optics
- Introduction of Wave Optics
- Huygens' Principle
- Refraction of a Plane Wave
- Refraction at a Rarer Medium
- Reflection of a Plane Wave by a Plane Surface
- Coherent and Incoherent Addition of Waves
- Interference of Light Waves and Young’s Experiment
- Diffraction of Light
- The Single Slit
- Seeing the Single Slit Diffraction Pattern
- Refraction of Monochromatic Light
- Polarisation
- Law of Malus
- Principle of Superposition of Waves
- Corpuscular Theory
- Plane Polarised Light
- The Validity of Ray Optics
- Doppler Effect
- Width of Central Maximum
- Resolving Power of Microscope and Astronomical Telescope
- Interference
- Proof of Laws of Reflection and Refraction Using Huygens' Principle
- Brewster's Law
- Fraunhofer Diffraction Due to a Single Slit
- Coherent and Incoherent Sources and Sustained Interference of Light
- Speed of Light
- Reflection and Refraction of Plane Wave at a Plane Surface Using Wave Fronts
- Overview: Wave Optics
Communication Systems
Dual Nature of Radiation and Matter
- Dual Nature of Radiation
- Electron Emission
- Photoelectric Effect - Hertz’s Observations
- Photoelectric Effect - Hallwachs’ and Lenard’s Observations
- Experimental Study of Photoelectric Effect
- Photoelectric Effect and Wave Theory of Light
- Einstein’s Photoelectric Equation: Energy Quantum of Radiation
- Particle Nature of Light: The Photon
- Einstein’s Equation - Particle Nature of Light
- Davisson and Germer Experiment
- de-Broglie Relation
- Wave Nature of Matter
- Overview: Dual Nature of Radiation and Matter
The Special Theory of Relativity
Atoms
- Introduction of Atoms
- Alpha-particle Scattering and Rutherford’s Nuclear Model of Atom
- Atomic Spectra
- Bohr’s Model for Hydrogen Atom
- Energy Levels
- The Line Spectra of the Hydrogen Atom
- De Broglie’s Explanation of Bohr’s Second Postulate of Quantisation
- Heisenberg and De Broglie Hypothesis
- Thompson Model
- Dalton's Atomic Theory
- Hydrogen Spectrum
- Overview: Atoms
Nuclei
- Atomic Masses and Composition of Nucleus
- Size of the Nucleus
- Mass - Energy
- Nuclear Binding Energy
- Nuclear Force
- Alpha Decay
- Beta Decay
- Gamma Decay
- Controlled Thermonuclear Fusion
- Nuclear Reactor
- Mass Defect and Binding Energy
- Atomic Mass, Mass - Energy Relation and Mass Defect
- Overview: Nuclei
- Law of Radioactive Decay
Semiconductor Electronics - Materials, Devices and Simple Circuits
- Concept of Semiconductor Electronics: Materials, Devices and Simple Circuits
- Classification of Metals, Conductors and Semiconductors
- Energy Bands in Conductors, Semiconductors and Insulators
- Intrinsic Semiconductor
- Extrinsic Semiconductor
- p-n Junction
- Semiconductor Diode
- Application of Junction Diode as a Rectifier
- Integrated Circuits
- Feedback Amplifier and Transistor Oscillator
- Transistor as a Device
- Basic Transistor Circuit Configurations and Transistor Characteristics
- Transistor Action
- Transistor: Structure and Action
- Digital Electronics and Logic Gates
- Transistor as an Amplifier (Ce-configuration)
- Transistor and Characteristics of a Transistor
- Zener Diode as a Voltage Regulator
- Special Purpose P-n Junction Diodes
- Diode as a Rectifier
- Triode
- Overview: Semiconductor Electronics
Communication Systems
- Detection of Amplitude Modulated Wave
- Production of Amplitude Modulated Wave
- Basic Terminology Used in Electronic Communication Systems
- Sinusoidal Waves
- Modulation and Its Necessity
- Amplitude Modulation (AM)
- Need for Modulation and Demodulation
- Satellite Communication
- Propagation of EM Waves
- Bandwidth of Transmission Medium
- Bandwidth of Signals
The Special Theory of Relativity
- The Special Theory of Relativity
- The Principle of Relativity
- Maxwell'S Laws
- Kinematical Consequences
- Dynamics at Large Velocity
- Energy and Momentum
- The Ultimate Speed
- Twin Paradox
Estimated time: 4 minutes
- Definition: Line of Force
- Characteristics of Electric Lines of Force
- Imaginary Lines, Real Uses
CBSE: Class 12
CISCE: Class 12
CISCE: Class 12
Definition: Electric Lines of Force
“An electric line of force is an imaginary smooth curve drawn in an electric field along which a free, isolated positive charge moves. The tangent drawn at any point on the electric line of force gives the direction of the force acting on a positive charge placed at that point.”
CBSE: Class 12
CISCE: Class 12
CISCE: Class 12
Key Points: Properties of the Electric Lines of Force
- Electric field lines originate from positive charges and terminate on negative charges (or at infinity).
- The tangent to a field line at any point gives the direction of the electric field; in a uniform field, the lines are parallel and straight.
- No two electric field lines intersect, as this would imply more than one direction of the electric field at a point.
- Electric field lines do not pass through a conductor, showing that the electric field inside a conductor is zero.
- The density of field lines indicates field strength—closer lines represent a stronger field, while wider spacing represents a weaker field; the lines are continuous and imaginary, though the field is real.
Shaalaa.com | Electric Charges and Fields part 21 (Properties of Electric field lines)
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