CBSE Class 12 Physics Important Questions 2027 — Chapter-Wise
Chapter-wise Class 12 Physics important questions for the 2027 CBSE board exam: derivations, numericals and theory, matched to the 2026-27 syllabus.
CBSE Class 12 Physics is 70 marks of theory and 30 of practicals. In the 2026-27 syllabus, Optics with EM Waves (18 marks) and Magnetism with EMI and AC (17) are half the theory paper. Below are important questions from each chapter: derivations, numericals and theory, all within the current syllabus.
Unit-Wise Marks (CBSE 2026-27)
| Unit | Chapters | Marks |
|---|---|---|
| Electrostatics; Current Electricity | Electric Charges and Fields, Electrostatic Potential and Capacitance, Current Electricity | 16 |
| Magnetic Effects of Current and Magnetism; EMI and AC | Moving Charges and Magnetism, Magnetism and Matter, Electromagnetic Induction, Alternating Current | 17 |
| Electromagnetic Waves; Optics | Electromagnetic Waves, Ray Optics and Optical Instruments, Wave Optics | 18 |
| Dual Nature of Radiation and Matter; Atoms and Nuclei | Dual Nature of Radiation and Matter, Atoms, Nuclei | 12 |
| Electronic Devices | Semiconductor Electronics | 7 |
| Total | — | 70 |
Electrostatics
| Question | Type |
|---|---|
| Derive the electric field of a dipole at a point on its axis and on its equatorial line. | Derivation |
| State Gauss's theorem and use it to find the field due to an infinitely long straight wire and a uniformly charged thin spherical shell (inside and outside). | Derivation |
| Derive the capacitance of a parallel plate capacitor with and without a dielectric between the plates. | Derivation |
| Two point charges of +3 μC and −3 μC are 20 cm apart. Find the electric field and the potential at the midpoint. | Numerical |
| Draw the field lines for (a) a positive charge, (b) a dipole, (c) two equal positive charges, and state three properties of field lines. | Diagram + theory |
| Capacitors of 2 μF, 3 μF and 6 μF are connected first in series, then in parallel. Find the equivalent capacitance in each case. | Numerical |
Current Electricity
| Question | Type |
|---|---|
| State Kirchhoff's rules and use them to find the currents in a given two-loop circuit. | Theory + numerical |
| Derive the balance condition of a Wheatstone bridge. | Derivation |
| What is drift velocity? Derive I = neAv_d and define mobility. | Derivation |
| A cell of emf 1.5 V and internal resistance 0.5 Ω is connected to a 2 Ω resistor. Find the current, the terminal voltage and the power in the resistor. | Numerical |
| Find the equivalent emf and internal resistance of two cells connected in parallel. | Derivation |
| How does the resistivity of a metal and of a semiconductor change with temperature? Explain why. | Theory |
Magnetism, EMI and AC
| Question | Type |
|---|---|
| State the Biot–Savart law and derive the magnetic field at the centre of a circular current loop. | Derivation |
| State Ampere's circuital law and use it to find the field of an infinitely long straight current-carrying wire. | Derivation |
| Derive the force per unit length between two parallel current-carrying conductors and use it to define the ampere. | Derivation |
| Explain the working of a moving coil galvanometer. How is it converted into (a) an ammeter, (b) a voltmeter? | Theory + diagram |
| State Faraday's laws of electromagnetic induction and explain Lenz's law with an example. | Theory |
| Describe an AC generator with a labelled diagram and draw the emf–time graph. | Theory + diagram |
| For a series LCR circuit, draw the phasor diagram, find the impedance and state the condition for resonance. | Derivation |
| Explain the working principle of a transformer and write the turns-ratio relation. | Theory |
Practise Physics chapter-wise
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Start freeEM Waves and Optics
| Question | Type |
|---|---|
| What is displacement current? List the parts of the electromagnetic spectrum in order and give one use of each. | Theory |
| Derive the lens maker's formula 1/f = (n−1)(1/R₁ − 1/R₂). | Derivation |
| Derive the relation for refraction at a spherical surface: n₂/v − n₁/u = (n₂ − n₁)/R. | Derivation |
| Draw the ray diagram of a compound microscope and write the expression for its magnifying power. | Diagram + theory |
| Explain total internal reflection, state its two conditions and give two applications. | Theory |
| Describe Young's double-slit experiment. Write the expression for fringe width (CBSE asks for the final expression, not its derivation) and use it in a numerical. | Theory + numerical |
| Use Huygens' principle to prove the laws of reflection or refraction of a plane wave. | Derivation |
| A convex lens of focal length 20 cm is in contact with a concave lens of focal length 25 cm. Find the power and focal length of the combination. | Numerical |
Dual Nature, Atoms and Nuclei
| Question | Type |
|---|---|
| State the observations of the photoelectric effect and explain them using Einstein's equation K_max = hν − φ₀. | Theory |
| The work function of a metal is 2.5 eV. Find its threshold frequency and the maximum kinetic energy of photoelectrons for light of frequency 8 × 10¹⁴ Hz. | Numerical |
| Find the de Broglie wavelength of an electron accelerated through 100 V. | Numerical |
| Using Bohr's postulates, derive the radius of the nth orbit and the energy of the electron in a hydrogen atom. | Derivation |
| Draw the energy level diagram of hydrogen and explain how spectral series arise. | Diagram + theory |
| Draw the graph of binding energy per nucleon against mass number and explain what it tells you about fission and fusion. | Theory + graph |
Semiconductor Electronics
| Question | Type |
|---|---|
| Explain forward and reverse biasing of a p-n junction with circuit diagrams and I-V characteristics. | Theory + diagram |
| Draw a full-wave rectifier circuit and explain its working with input and output waveforms. | Diagram + theory |
| Distinguish between intrinsic and extrinsic semiconductors, and between p-type and n-type. | Theory |
Not in the CBSE 2026-27 Board Exam
Older question banks still carry these; skip them for the CBSE Board exam (other boards and entrance exams may still include some of them): the Van de Graaff generator, meter bridge and potentiometer, Ampere's law for the solenoid beyond a qualitative idea, polarisation (Malus's and Brewster's laws), radioactive decay and half-life, logic gates, and communication systems.
Unit marks and topic coverage follow CBSE's Class 12 Physics syllabus for 2026-27. Work through every NCERT exercise before using this list for revision.
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Start freeFrequently Asked Questions
Which chapters are most important for Class 12 Physics?
Go by CBSE's 2026-27 unit marks: Electromagnetic Waves and Optics 18, Magnetic Effects of Current, Magnetism, EMI and AC 17, Electrostatics and Current Electricity 16, Dual Nature, Atoms and Nuclei 12, and Electronic Devices 7, for a 70-mark theory paper. Optics and the magnetism/EMI unit together are half the paper.
How many derivations are asked in the Physics board exam?
CBSE doesn't fix a number, but the three 5-mark long-answer questions often ask for a derivation. Know these well: electric field of a dipole, Gauss's law applications, capacitance of a parallel plate capacitor, drift velocity and current, field at the centre of a circular loop, the lens maker's formula, refraction at a spherical surface, and Bohr's radius and energy expressions.
Are numericals important in Class 12 Physics?
Yes. Numericals come up across the paper, most often from Current Electricity (Kirchhoff's rules, Wheatstone bridge, cells), Ray Optics (mirror and lens formulas, power), Alternating Current (reactance, impedance, resonance) and Dual Nature (photoelectric effect, de Broglie wavelength).
How should I prepare Physics in the last month?
(1) Revise all formulas daily for 15 minutes. (2) Solve 10 numericals a day. (3) Write one derivation from memory every day. (4) Solve a sample paper every few days under timed conditions. (5) Practise labelled diagrams. Steady practice beats last-minute cramming.