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Important Definitions & Theory
Complete Syllabus (Ch 1-14) • Click items for Answers
Electric Charges & Fields Unit 1
Key Definitions
- Electric Dipole Moment
- Electric Flux
- Linear/Surface/Volume Charge Density
- Quantization of Charge
Important Questions
- Why do two electric field lines never intersect?
- Why is the electric field inside a conductor zero?
- Why must electrostatic field lines be normal to the surface of a conductor?
- Draw field lines for (a) q > 0, (b) q < 0, (c) Dipole, (d) Two like charges.
Potential & Capacitance Unit 1
Key Definitions
- Equipotential Surface
- Electrostatic Potential Energy
- Dielectric Constant (K)
- Dielectric Strength
- Capacitance
Important Questions
- What is the work done in moving a charge on an equipotential surface?
- Why does capacitance increase when a dielectric slab is inserted?
- What happens to Energy, Charge, and Voltage when a battery is disconnected vs. connected?
- Can two equipotential surfaces intersect? Explain.
Current Electricity Unit 2
Key Definitions
- Drift Velocity
- Relaxation Time
- Mobility
- Current Density
- EMF
- Internal Resistance
Important Questions
- Why are alloys like Manganin/Constantan used for making standard resistors?
- Explain the limitations of Ohm’s Law with graphs (GaAs, Diode).
- Why is a Potentiometer preferred over a Voltmeter for measuring EMF?
- How does drift velocity change with temperature?
Moving Charges & Magnetism Unit 3
Key Definitions
- Ampere’s Circuital Law (Statement)
- Biot-Savart Law (Statement)
- One Ampere (Standard def)
- Velocity Selector
- Current Sensitivity
Important Questions
- Why is an Ammeter connected in series and Voltmeter in parallel?
- How do you convert a Galvanometer into (a) Ammeter, (b) Voltmeter?
- Why does a magnetic field do no work on a moving charge?
- Under what condition does a charged particle move undeviated in combined E and B fields?
Magnetism & Matter Unit 3
Key Definitions
- Magnetic Dipole Moment
- Magnetic Susceptibility
- Permeability
- Coercivity, Retentivity
- Angle of Dip
- Magnetic Meridian
Important Questions
- Distinguish between Diamagnetic, Paramagnetic, and Ferromagnetic materials.
- Why are field lines of a magnet continuous loops?
- Why is Soft Iron used for electromagnets and Steel for permanent magnets?
- What is the value of the Angle of Dip at the (a) Equator, (b) Poles?
Electromagnetic Induction Unit 4
Key Definitions
- Magnetic Flux
- Electromagnetic Induction
- Self-Inductance
- Mutual Inductance
- Eddy Currents
Important Questions
- State Lenz’s Law and show how it obeys Conservation of Energy.
- How can Eddy currents be minimized?
- Two circular coils are placed coaxially. Finding direction of induced current.
- Why does the inductance of a solenoid increase when an iron core is inserted?
Alternating Current Unit 4
Key Definitions
- RMS Value
- Inductive/Capacitive Reactance
- Impedance
- Power Factor
- Wattless Current
- Q-Factor
- Resonance
Important Questions
- Why is a Choke Coil preferred over a resistor to control AC?
- What is the phase relationship between V and I in Pure L, Pure C, and Pure R circuits?
- Why can't a transformer work on DC?
- Define "Sharpness of Resonance" and its relation to the Q-value.
Electromagnetic Waves Unit 5
Key Definitions
- Displacement Current
- Electromagnetic Spectrum
Important Questions
- Identify the EM wave used for: (a) Radar, (b) LASIK, (c) Cancer treatment, (d) Remote controls.
- Show that EM waves carry momentum (Radiation Pressure concept).
- What is the source of EM waves?
- Why is the ozone layer crucial?
Ray Optics Unit 6
Key Definitions
- Total Internal Reflection (TIR)
- Critical Angle
- Power of Lens
- Linear Magnification, Angular Magnification
Important Questions
- What are the conditions for TIR?
- Why does the sky appear blue? Why does the sun appear red at sunset?
- Why do stars twinkle but planets do not?
- Draw ray diagrams for Compound Microscope and Telescope.
Wave Optics Unit 6
Key Definitions
- Wavefront (Plane/Spherical)
- Huygens’ Principle
- Interference
- Diffraction
- Polarization
- Malus Law
Important Questions
- Differentiate between Interference and Diffraction.
- Why can two independent light sources not produce an interference pattern?
- Does the appearance of fringes change if the YDSE apparatus is immersed in water?
- What is the shape of the wavefront emerging from (a) Point source, (b) Distant source?
Dual Nature Unit 7
Key Definitions
- Work Function
- Threshold Frequency
- Stopping Potential
- Photoelectric Effect
- De-Broglie Wavelength
Important Questions
- Why is wave theory unable to explain the photoelectric effect?
- Draw graphs for: (a) Current vs Intensity, (b) Stopping Potential vs Frequency.
- Why do alkali metals show photoelectric effect with visible light?
- Show that the de-Broglie wavelength of a photon equals the wavelength of EM radiation of that photon.
Atoms Unit 8
Key Definitions
- Distance of Closest Approach
- Impact Parameter
- Ionization Energy
- Excitation Energy
Important Questions
- State Bohr’s quantization condition of angular momentum.
- Why does the total energy of an electron have a negative sign?
- Draw the spectral series of Hydrogen (Lyman, Balmer, Paschen...) and identify their regions.
Nuclei Unit 8
Key Definitions
- Mass Defect
- Binding Energy
- Nuclear Force
- Half-Life
- Mean Life
- Nuclear Fission/Fusion
Important Questions
- Draw the Binding Energy per Nucleon curve. Explain stability based on it.
- Why is nuclear density constant (independent of mass number)?
- Compare Nuclear forces with Coulomb forces.
- Why is heavy water used as a moderator in reactors?
Semiconductors Unit 9
Key Definitions
- Intrinsic/Extrinsic Semiconductor
- Doping
- Energy Band Gap
- Depletion Region
- Barrier Potential
- Rectification
Important Questions
- Distinguish between n-type and p-type semiconductors.
- Why is a photodiode always operated in reverse bias?
- Draw Energy Band diagrams for Conductor, Semiconductor, and Insulator.
- Explain the formation of the depletion region in a PN junction.
