Chapter 1: Electric Charges and Fields — Derivations
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Torque on an electric dipole in a uniform electric field
τ = p × E -
Electric field due to an infinitely long straight uniformly charged wire (using Gauss’s law).
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Electric field due to a uniformly charged thin spherical shell (outside and on surface).
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Electric field intensity on the axial line of an electric dipole.
Chapter 2: Electrostatic Potential and Capacitance — Derivations
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Capacitance of a parallel plate capacitor
C = ε₀A / d -
Equivalent capacitance of capacitors connected in series.
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Equivalent capacitance of capacitors connected in parallel.
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Energy stored in a capacitor
U = ½CV² -
Electric potential due to an electric dipole.
Chapter 3: Current Electricity — Derivations
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Equivalent resistance of resistors in parallel.
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Wheatstone bridge balance condition
P/Q = R/S -
Meter bridge formula to find unknown resistance.
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Microscopic form of Ohm’s law
R = ml / (ne²τA)
Chapter 4: Moving Charges and Magnetism — Derivations
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Torque on a rectangular current loop in a uniform magnetic field
τ = m × B -
Magnetic field on the axis of a circular current loop.
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Magnetic field inside a solenoid using Ampere’s circuital law
B = μ₀nI -
Force between two parallel current-carrying conductors.
Chapter 5: Magnetism and Matter
No derivations asked (only theory-based questions).
Chapter 6: Electromagnetic Induction — Derivations
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Expression for induced emf in an AC generator
e = NBAω sin(ωt) -
Self-inductance of a solenoid.
Chapter 7: Alternating Current — Derivations
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Current through a resistor when AC voltage is applied.
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Impedance of a series LCR circuit
Z = √[R² + (Xₗ − Xc)²] -
Condition for resonance (impedance minimum).
Chapter 8: Electromagnetic Waves
No derivations asked.
Chapter 9: Ray Optics and Optical Instruments — Derivations
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Lens maker’s formula.
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Refraction at a spherical surface
n₂/v − n₁/u = (n₂ − n₁)/R -
Magnifying power of a simple microscope.
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Refractive index of a prism at minimum deviation.
Chapter 10: Wave Optics — Derivations
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Reflection of light using Huygens principle.
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Refraction (Snell’s law) using Huygens principle.
Chapters 11–14 (Dual Nature, Atoms, Nuclei, Semiconductor)
No derivations — only definitions, laws, numericals, and diagrams.
