Important Questions for CBSE Class 12 Physics (Chapter-Wise)
Are you searching for Important Questions for CBSE Class 12 Physics to score full marks in your board exam? This page is made for Class 12 students who want quick, simple, and exam-focused revision. CBSE Class 12 Physics important questions cover every unit, from Electrostatics to Semiconductor Electronics, and are chosen based on past board papers and the latest CBSE sample paper pattern. Physics is a scoring subject once you understand the concepts and remember the right formulas. Many students lose marks not because they did not study, but because they did not know which topics carry more weight in the exam. This page lists the most important questions for the CBSE Class 12 Physics board exam, along with easy, mobile-friendly formula tables for every chapter. Whether you are revising a week before the exam or starting fresh today, these CBSE Class 12 Physics important questions and answers will help you focus on what truly matters. At MyClass24, we believe smart revision beats long hours of unplanned study. So let us go chapter by chapter and see which questions and formulas you must never skip before your Physics board exam.
Find PDFs of all chapters of Important Questions for CBSE Class 12 Physics
Why Important Questions Matter for CBSE Class 12 Physics
CBSE Class 12 Physics has a fixed weightage for every unit as per the CBSE Class 12 Physics syllabus, and board papers repeat similar question patterns every year. Practising chapter-wise important questions for Class 12 Physics helps you spend less time guessing and more time mastering high-weightage topics like Electrostatics, Current Electricity, and Optics. It also builds confidence, improves speed, and reduces silly mistakes in numerical problems, which is where most students lose easy marks.
Download PDFs of Important Questions for Every Chapter of CBSE Class 12 Physics
Chapter-Wise Important Questions for CBSE Class 12 Physics
1. Electrostatics and Electric Charges
Important topics: Coulomb's law, electric field and potential, Gauss's theorem, dipoles, and capacitors. These are frequently asked as important questions on Electrostatics for Class 12.
State Gauss's theorem and use it to find the electric field due to an infinite charged sheet.
Derive an expression for the electric field on the axis of a dipole.
Explain the effect of a dielectric on the capacitance of a parallel plate capacitor.
Concept | Formula |
Coulomb's Law | F = kq1q2 / r^2 |
Electric Field | E = F / q = kq / r^2 |
Electric Potential | V = kq / r |
Capacitance (parallel plate) | C = ε0A / d |
Energy stored in capacitor | U = 1/2 CV^2 |
2. Current Electricity
This chapter is a regular source of important numerical questions for Class 12 Physics, especially on Kirchhoff's laws and the Wheatstone bridge.
State and explain Kirchhoff's current and voltage laws with examples.
Derive the condition for balance in a Wheatstone bridge.
Explain the effect of temperature on the resistivity of conductors and semiconductors.
Concept | Formula |
Ohm's Law | V = IR |
Resistivity | R = ρl / A |
Electric Power | P = VI = I^2R |
Terminal Voltage (cell) | V = E − Ir |
3. Moving Charges and Magnetism
Expect important questions on magnetic effects of current based on the Biot-Savart law, Ampere's circuital law, and force on a current-carrying conductor.
State the Biot-Savart law and use it to find the magnetic field at the centre of a current loop.
Derive the expression for force between two parallel current-carrying conductors.
Explain the working principle of a moving coil galvanometer.
Concept | Formula |
Biot-Savart Law | dB = (μ0 / 4π) × (I dl sinθ / r^2) |
Ampere's Circuital Law | ∮B.dl = μ0 I |
Force on a Conductor | F = BIl sinθ |
Torque on Current Loop | τ = NIAB sinθ |
4. Electromagnetic Induction and Alternating Current
This unit brings many important derivations for Class 12 Physics such as self-induction, mutual induction, and impedance in AC circuits. Before Solving the Important Questions one must solve NCERT solutions with the help of NCERT solutions for Class 12.
State Faraday's laws and Lenz's law of electromagnetic induction.
Derive the expression for impedance of a series LCR circuit.
Explain resonance in an AC circuit and its practical significance.
Concept | Formula |
Induced EMF | ε = −N (dΦ/dt) |
Self Inductance | ε = −L (dI/dt) |
Impedance (LCR circuit) | Z = √[R^2 + (XL − XC)^2] |
Resonant Frequency | f = 1 / (2π√LC) |
5. Electromagnetic Waves
Short-answer important questions on EM waves usually cover properties and the electromagnetic spectrum.
List the properties of electromagnetic waves and name their sources.
Arrange the electromagnetic spectrum in order of increasing frequency with uses of each region.
6. Ray Optics and Wave Optics
Optics is one of the highest-scoring units, with several important numericals on lenses, mirrors, and interference asked every year.
Derive the lens maker's formula for a thin convex lens.
Explain Young's double slit experiment and derive the fringe width formula.
Describe total internal reflection with real-life applications like optical fibres.
Concept | Formula |
Mirror Formula | 1/v + 1/u = 1/f |
Lens Maker's Formula | 1/f = (n−1)(1/R1 − 1/R2) |
Magnification (lens) | m = v/u |
Fringe Width (YDSE) | β = λD / d |
7. Dual Nature of Radiation and Matter
This chapter has short, concept-based important questions on the photoelectric effect and de Broglie wavelength.
State Einstein's photoelectric equation and explain the concept of threshold frequency.
Derive the expression for the de Broglie wavelength of a moving particle.
Concept | Formula |
Photoelectric Equation | eV0 = hν − φ0 |
De Broglie Wavelength | λ = h / p = h / mv |
8. Atoms and Nuclei
Frequently tested important questions on Bohr's model and radioactivity appear in this chapter.
Explain Bohr's postulates and derive the radius of the nth orbit of hydrogen atom.
State the law of radioactive decay and define half-life.
Concept | Formula |
Radius of nth Orbit | rn = n^2h^2ε0 / πmZe^2 |
Radioactive Decay Law | N = N0 e^(−λt) |
Half-Life | T = 0.693 / λ |
Mass-Energy Relation | E = mc^2 |
9. Semiconductor Electronics
This unit brings scoring important questions on diodes and transistors that are direct and formula-based.
Explain the working of a p-n junction diode as a rectifier.
Differentiate between an intrinsic and an extrinsic semiconductor.
Concept | Formula |
Current Gain (Common Emitter) | β = Ic / Ib |
Current Gain (Common Base) | α = Ic / Ie |
Relation between α and β | β = α / (1 − α) |
Preparation Tips for CBSE Class 12 Physics Board Exam
Revise NCERT theory first, since most CBSE Class 12 Physics important questions are directly based on NCERT lines.
Practice previous year board papers and CBSE sample papers to spot repeated patterns.
Keep a separate formula sheet for each unit and revise it daily in the last two weeks.
Attempt numerical problems with proper units, since CBSE awards step-wise marks.
Draw neat, labelled diagrams wherever asked, as diagrams carry dedicated marks.