Topics
Electric Charges and Fields
- Electric Charge
- Electrical Conduction in Solids
- 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
- Charging by Induction
- Uniformly Charged Infinite Plane Sheet and Uniformly Charged Thin Spherical Shell (Field Inside and Outside)
- Overview: Gauss' Theorem
- Conductors and Insulators
- Electric Field due to an Electric Dipole
Electrostatics
Electrostatic Potential and Capacitance
- Electric Potential
- Potential Due to a Point Charge
- Potential Due to an Electric Dipole
- 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
- 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
- Conductors and Insulators Related to Electric Field
- Electric Potential
- Overview: Electric Potential
- Overview: Capacitors and Dielectrics
Current Electricity
Current Electricity
- Electric Current
- Electric Current and Its Related Concepts
- Ohm's Law
- 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
- Resistors in Parallel
- Specific Resistance or Electrical Resistivity
- 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
Magnetic Effects of Current and Magnetism
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
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- Applications of Biot-Savart's Law > Magnetic Field on the Axis of a Circular Current-Carrying 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
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- Magnetic Diapole
- Torque on a Current-Loop in a Uniform Magnetic Field
- Force on a Current Carrying Conductor in a 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 Induction and Alternating Currents
Electromagnetic Waves
Magnetism and Matter
- Concept of Magnetism
- Bar Magnet and Solenoid Analogy
- 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 Due to Magnetic Dipole (Bar Magnet)
- Magnetic Field due to a Bar Magnet
- Magnetic Dipole Moment of a Revolving Electron
- Current Loop as a Magnetic Dipole
- Magnetic Substances
- Overview: Magnetism and Mater
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
Optics
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
Dual Nature of Radiation and Matter
Electromagnetic Waves
- Elementary Facts About Electromagnetic Wave Uses
- Electromagnetic Spectrum
- Transverse Nature of Electromagnetic Waves
- EM Wave
- Displacement Current
- Overview of Electromagnetic Waves
Atoms and Nuclei
Electronic Devices
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
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- 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
Communication Systems
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
- Electric Polarisation of Matter
- 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
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
- Composition of Nucleus
- Size of the Nucleus
- Mass - Energy
- Binding Energy per Nucleon
- 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 Solids
- Intrinsic Semiconductor
- Extrinsic Semiconductor
- Diode or p-n Junction
- Semiconductor Diode
- p-n 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
- Voltage Regulator
- Special Purpose P-n Junction Diodes
- p-n Junction 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: 2 minutes
CBSE: Class 12
Key Points: Refraction at a Rarer Medium
When light travels from optically denser to rarer medium obliquely:
- It bends away from the normal.
- Angle of refraction > angle of incidence.
If angle of incidence exceeds the Critical Angle (C), total internal reflection occurs.
Critical Angle: \[C=\sin^{-1}\left(\frac{\mu_{2}}{\mu_{1}}\right),\mathrm{where~}\mu_{1}>\mu_{2}.\]
At critical angle, refracted ray grazes the surface (angle of refraction = 90°).
Related QuestionsVIEW ALL [6]
| A ray of light travels from a denser to a rarer medium. After refraction, it bends away from the normal. When we keep increasing the angle of incidence, the angle of refraction also increases till the refracted ray grazes along the interface of two media. The angle of incidence for which it happens is called critical angle. If the angle of incidence is increased further the ray will not emerge and it will be reflected back in the denser medium. This phenomenon is called total internal reflection of light. |
For which of the following media, with respect to air, the value of critical angle is maximum?
| A ray of light travels from a denser to a rarer medium. After refraction, it bends away from the normal. When we keep increasing the angle of incidence, the angle of refraction also increases till the refracted ray grazes along the interface of two media. The angle of incidence for which it happens is called critical angle. If the angle of incidence is increased further the ray will not emerge and it will be reflected back in the denser medium. This phenomenon is called total internal reflection of light. |
A ray of light travels from a medium into the water at an angle of incidence of 18°. The refractive index of the medium is more than that of water and the critical angle for the interface between the two media is 20°. Which one of the following figures best represents the correct path of the ray of light?
