NIOS Class 12 Physics Important Questions (Physics 312) 2026 Complete Study & Exam Preparation Guide

NIOS Class 12 Physics 312 Important Questions 2026 – Chapter-Wise Objective Question Bank

Physics is the subject where students understand a concept during study and then lose the mark in the exam because they practised reading, not answering. If you are preparing for NIOS Class 12 Physics (Code 312) in 2026 and want the most important chapter-wise objective questions from the actual Unnati Education booklet, this page gives you exactly that. Sample questions with answers are included. For the complete solution booklet, contact Unnati Education at 9654279279 or 9899436384.

NIOS Physics 312 – Quick Subject Overview

What Are NIOS Class 12 Physics 312 Important Questions for 2026?

Physics rewards students who prepare with questions, not just with notes. You can understand Newton's third law completely and still pick the wrong MCQ option because the exam puts four very close-looking answers in front of you. Knowing that Lenz's Law is a consequence of conservation of energy is different from recognising it as the right option when the other three options sound equally plausible. NIOS Physics 312 covers 8 modules and 30 lessons — from laws of motion and thermodynamics to optics, atomic structure, and semiconductors. The objective section tests formula recall, conceptual understanding, and numerical accuracy together. This page gives you the most important sample questions from the actual Unnati Education Physics 312 booklet. For the complete chapter-wise solution booklet with full working and explanations, get in touch with Unnati Education.

Module I – Motion, Force and Energy

Lesson 3 – Laws of Motion

Laws of Motion is one of the highest-value chapters in the objective section. Inertia, Newton's three laws, conservation of momentum, friction, and pseudo forces are all tested directly. The exam does not just ask you to state a law — it gives you a scenario and asks which law it illustrates, or gives you numbers and asks for the result.

Students who need their NIOS Class 12 TMA for Physics 312 solved accurately and ready for submission can get it from Unnati Education in both typed and handwritten formats.

Sample Questions

Which physical quantity is the best measure of the inertia of an object? A. Volume B. Acceleration C. Mass D. Force
Answer: C

A marble rolls on a frictionless horizontal surface indefinitely. This illustrates: A. Newton's third law B. Inertia of direction C. Newton's first law D. Kinetic energy conservation
Answer: C

A force of 10 N acts on a 2 kg object for 3 seconds. The change in momentum is: A. 5 kg·m/s B. 10 kg·m/s C. 30 kg·m/s D. 60 kg·m/s
Answer: C (Impulse = F × t = 10 × 3 = 30 N·s = Δp)

A bullet of 0.01 kg is fired at 500 m/s from a gun of mass 1 kg. The recoil velocity of the gun is: A. 5 m/s B. 0.5 m/s C. −5 m/s D. −0.5 m/s
Answer: D (mv + MV = 0 → V = −0.01 × 500 / 1 = −0.5 m/s)

Fill in the Blank The property of a body by virtue of which it resists any change in its state of rest or uniform motion is called __________.
Answer: Inertia

True or False Ball bearings reduce friction by converting sliding friction into rolling friction.
Answer: True

The recoil velocity question is a direct application of conservation of momentum. The total momentum of the system (bullet + gun) is zero before firing, so it must remain zero after. Write the equation mv + MV = 0, substitute the values, and the answer takes under fifteen seconds.

Lesson 6 – Work, Energy and Power

Work, energy, and power questions require careful attention to direction. Work done by gravitational force when lifting a mass upward is negative (−mgh), not positive — because force and displacement are in opposite directions. The exam specifically uses this sign distinction to create wrong answer options.

Sample Questions

A constant force F⃗ = (3 î + 4 ĵ) N displaces a particle by d⃗ = (2 î − 3 ĵ) m. The work done by the force is: A. −6 J B. 6 J C. −1 J D. −18 J
Answer: A (W = F⃗ · d⃗ = 3 × 2 + 4 × (−3) = 6 − 12 = −6 J)

Work done by gravitational force when lifting a mass m to height h is: A. −mgh B. +mgh C. Zero D. Depends on velocity
Answer: A

A block is lowered from height h to the ground. Work done by gravitational force is: A. −mgh B. +mgh C. 0 D. Depends on mass
Answer: B

Fill in the Blank Kinetic energy of a body of mass m moving with velocity v is __________.
Answer: ½mv²

True or False Work done by a force is zero when the force is perpendicular to the displacement.
Answer: True

Module III – Thermal Physics

Lesson 11 – Thermodynamics

Thermodynamics is a module where students lose marks because they confuse the four thermodynamic processes — isothermal, adiabatic, isochoric, isobaric — and the condition that defines each one. The exam tests this directly.

Students who want comprehensive practice across all 30 lessons can get the complete NIOS Class 12 Important Questions booklet for Physics 312 from Unnati Education with full solutions and step-by-step working.

Sample Questions

Which one of the following statements defines the Zeroth Law of Thermodynamics? A. Temperature of a system is constant in thermal equilibrium B. Heat always flows from higher to lower temperature C. If A is in equilibrium with B, and B with C, then A is in equilibrium with C D. Pressure and volume are state variables of a system
Answer: C

Which of the following correctly identifies an adiabatic process? A. A process where temperature remains constant B. A process where pressure remains constant C. A process in which ΔQ = 0 D. A process in which ΔW = 0
Answer: C

What is the mathematical form of the First Law of Thermodynamics? A. ΔU = −ΔQ + ΔW B. ΔQ = ΔU + ΔW C. ΔQ = ΔW − ΔU D. ΔW = ΔU − ΔQ
Answer: B

Fill in the Blank In an adiabatic process, no __________ is exchanged between the system and its surroundings.
Answer: heat

True or False Internal energy is a state function that depends only on the current state (P, V, T) of the system.
Answer: True

ΔQ = ΔU + ΔW is the First Law. The exam tests this in all three rearranged forms — finding ΔU when ΔQ and ΔW are given, finding ΔW when ΔQ and ΔU are given, and finding ΔQ when the other two are given. Practise all three directions.

Module IV – Wave Phenomena

Lesson 14 – Wave Phenomena

Wave questions from this lesson test the relationship between wave speed, frequency, and wavelength, the correction Laplace made to Newton's formula for speed of sound, and what happens to a wave when it reflects from a denser medium.

Sample Questions

Newton's formula for the velocity of sound in a gas fails because it assumes: A. High elasticity B. Low density C. Isothermal changes D. Adiabatic changes
Answer: C

The reflection of a transverse wave from a denser medium causes: A. No phase change B. Reversal of velocity C. Phase change of π D. Decrease in amplitude
Answer: C

A wave has a frequency of 50 Hz and wavelength 20 m. The phase difference between two points separated by 5 m is:
Answer: π

Fill in the Blank The SI unit of frequency is __________.
Answer: hertz (Hz)

Newton assumed isothermal compression and rarefaction, which gave a speed of sound value that was incorrect. Laplace corrected it by recognising the process is actually adiabatic. This correction appears in objective questions every year — know which scientist made the error and which one corrected it.

Module V – Electricity and Magnetism

Lesson 15 – Electric Charge and Electric Field and Lesson 16 – Electric Potential and Capacitors

Module V has the highest density of objective questions in the entire paper. Coulomb's law, electric field direction, permittivity, capacitor energy, and Ohm's law are all tested directly. The reason Coulomb force in water is weaker than in air is because water has higher permittivity — the exam uses this as an MCQ every year.

Students who want to study from actual NIOS past papers can get NIOS Class 12 question paper collections for Physics 312 from Unnati Education, covering multiple exam cycles with complete solutions.

Sample Questions

A glass rod is rubbed with silk and acquires a charge of +3.2 × 10⁻¹⁷ C. The charge on the silk is: A. Zero B. +3.2 × 10⁻¹⁷ C C. −3.2 × 10⁻¹⁷ C D. Depends on mass
Answer: C

Coulomb force in air is stronger than in water because: A. Water has high density B. Water has low permittivity C. Water has high permittivity D. Air molecules are polar
Answer: C

Fill in the Blank Electric charge is quantised as Q = __________, where n is an integer and e = 1.6 × 10⁻¹⁹ C.
Answer: ne

True or False A capacitor stores energy in its electric field between the plates.
Answer: True

Lesson 17 – Electric Current and Lesson 18 – Magnetism

Electric current questions test drift velocity, the temperature dependence of resistance, and circuit instruments. Semiconductor materials like silicon have negative temperature coefficient — their resistivity decreases with temperature — which is opposite to metals. This distinction is tested in objective questions consistently.

Sample Questions

In which of the following materials does resistivity decrease with an increase in temperature? A. Nichrome B. Manganin C. Silicon D. Copper
Answer: C

Two wires of the same material and length have radii in the ratio 1:2. Their resistance ratio is: A. 1:4 B. 4:1 C. 1:16 D. 16:1
Answer: B

Which device operates on the principle of the null method? A. Voltmeter B. Galvanometer C. Potentiometer D. Ammeter
Answer: C

Which of the following properties of a magnet proves that Earth itself behaves like a magnet? A. Attractive property B. Magnetic induction C. Directive property D. Poles are inseparable
Answer: C

Fill in the Blank The direction of magnetic field due to a straight current-carrying wire is __________ to the circular field lines around the wire.
Answer: tangential (tangent)

Students who need NIOS Class 12 Intext and Terminal Questions for Physics 312 can get a complete chapter-wise set from Unnati Education for thorough preparation across all modules.

Lesson 19 – Electromagnetic Induction and Alternating Current

Faraday's law, Lenz's law, self-induction, and eddy currents are all tested from this lesson. The induced emf calculation appears as a direct numerical MCQ and is one of the most reliable marks in Module V.

Sample Questions

A coil of 100 turns and area 0.01 m² is placed in a magnetic field perpendicular to its plane. If the magnetic field changes from 2 T to 0 T in 0.05 s, the magnitude of the induced emf is: A. 40 V B. 20 V C. 10 V D. 0 V
Answer: A (EMF = N × ΔΦ/Δt = 100 × 0.01 × 2/0.05 = 40 V)

Lenz's Law is a consequence of: A. Newton's Third Law B. Conservation of energy C. Conservation of momentum D. Gauss's Law
Answer: B

A coil has self-inductance 2 H. The emf developed when current changes from 3 A to 0 A in 0.01 s is: A. 600 V B. 300 V C. −600 V D. −300 V
Answer: A (EMF = L × ΔI/Δt = 2 × 3/0.01 = 600 V)

True or False Eddy currents are reduced by laminating the iron core of a transformer.
Answer: True

Module VI – Optics and Optical Instruments

Lesson 21 – Dispersion and Scattering of Light

Dispersion, the prism, angular dispersion, and scattering of light are all tested from this lesson. The condition for observing dispersion, the formula for angular dispersion (δᵥ − δᴿ), and the reason why the sky appears blue are standard objective questions.

Sample Questions

Which of the following conditions is necessary for observing dispersion of light in a medium? A. Medium must be non-dispersive B. All wavelengths should have the same speed C. Separation of component wavelengths with no recombination D. Medium must be vacuum
Answer: C

Angular dispersion is defined as: A. Difference between angles of refraction B. Sum of deviations of red and violet C. δᵥ − δᴿ D. μᵥ − μᴿ
Answer: C

Fill in the Blank The refractive index of a medium is __________ for shorter wavelengths than for longer wavelengths.
Answer: greater (higher)

True or False Violet light deviates more than red light when passing through a prism.
Answer: True

Module VII – Atoms and Nuclei

Lesson 24 – Structure of Atom

Rutherford's experiment, Bohr's model, spectral series, and the relationship between orbit number and radius are all tested from this lesson. The ratio of radii of Bohr orbits (rₙ = n²a₀) is a direct calculation that appears in MCQ format every year.

Sample Questions

In Rutherford's experiment, the observation of a few α-particles being deflected at large angles (>90°) led to the conclusion that: A. Atoms are mostly empty space B. Electrons carry the entire atomic mass C. Positive charge is spread throughout the atom D. Electrons are heavier than α-particles
Answer: A

Rutherford's model failed to explain: A. The charge of an electron B. The existence of a nucleus C. The stability of atom and discrete spectra D. The motion of α-particles
Answer: C

What is the ratio of radii of the third and second Bohr orbits of hydrogen? A. 9:4 B. 3:2 C. 4:9 D. 1:2
Answer: A (r₃/r₂ = 3²/2² = 9/4)

Which spectral series lies in the ultraviolet region? A. Balmer B. Paschen C. Lyman D. Brackett
Answer: C

Fill in the Blank The radius of the nth orbit of a hydrogen atom is proportional to __________.
Answer: n²

Lesson 27 – Nuclear Fission and Fusion

Nuclear questions test the energy source of stars, the average number of neutrons released per fission, and why neutrons are better projectiles than protons for initiating nuclear reactions.

Sample Questions

Which of the following correctly explains the energy source of the sun? A. Nuclear fission of heavy elements B. Chemical burning of hydrogen C. Fusion of hydrogen nuclei into helium D. Fission of uranium isotopes in the core
Answer: C

Why are neutrons considered ideal projectiles for initiating nuclear reactions? A. They are negatively charged B. They do not experience Coulomb repulsion C. They are heavier than protons D. They have high ionising power
Answer: B

The energy released in the fission of one U-235 nucleus is approximately: A. 2 MeV B. 200 MeV C. 20 MeV D. 2000 MeV
Answer: B

Fill in the Blank On average, __________ neutrons are released per fission of U-235, enabling the possibility of a chain reaction.
Answer: 2.54

Module VIII – Semiconductors and Communication Systems

Lesson 28 – Semiconductors and Semiconducting Devices

Semiconductors are tested for intrinsic versus extrinsic behaviour, doping groups, and p-n junction properties. The majority carriers in p-type material are holes and in n-type material are electrons — this pair gets tested every year in multiple formats.

Sample Questions

In an intrinsic semiconductor at 300K, the electron and hole concentrations are: A. 0 B. Unequal C. Equal D. Cannot be predicted
Answer: C

Which group element is used for doping silicon to form an n-type semiconductor? A. Group III B. Group IV C. Group V D. Group VI
Answer: C

In a p-type semiconductor, majority carriers are: A. Electrons B. Holes C. Both D. None
Answer: B

The depletion region in a p-n junction: A. Contains only free electrons B. Contains only holes C. Has no free charge carriers D. Conducts current freely
Answer: C

Fill in the Blank In a p-n junction, the p-type semiconductor contains __________ as majority carriers.
Answer: holes

True or False In an n-type semiconductor, the majority carriers are electrons.
Answer: True

Most Repeated Topics in NIOS Physics 312 Exams

These are the areas that appear most consistently across multiple years of objective questions in NIOS Physics 312.

Conservation of momentum and Newton's first law from Lesson 3 appear in every paper. Work done against gravity and kinetic energy formula from Lesson 6 are tested as numerical MCQs regularly. The First Law of Thermodynamics ΔQ = ΔU + ΔW and the definition of an adiabatic process from Lesson 11 appear every cycle. Laplace's correction to Newton's formula from Lesson 14 is a standard one-mark question. Coulomb's law and the effect of permittivity on electric force from Lesson 15 are tested every year. The induced emf numerical from Faraday's law in Lesson 19 and Lenz's Law as conservation of energy are both reliable questions. The Lyman series in the ultraviolet region and ratio of Bohr orbit radii from Lesson 24 appear repeatedly. The majority carrier distinction (p-type holes, n-type electrons) from Lesson 28 is tested in every exam cycle without exception.

Quick Reference – Key Formulas by Module

Common Mistakes Students Make in Physics 312 Exam

Writing that work done by gravity during lifting is +mgh is the most common sign error in Module I — the correct answer is −mgh because force and displacement are in opposite directions. Confusing isothermal (ΔT = 0) with adiabatic (ΔQ = 0) in thermodynamics costs marks in true or false questions every year. Saying Newton was right about the speed of sound formula when it was actually Laplace who corrected him — this mix-up appears in assertion-type MCQs. Thinking Silicon's resistivity increases with temperature (like metals) when in fact it decreases is a classic semiconductor error. Confusing Lyman series (UV) with Balmer series (visible) leads to wrong answers in the atomic structure section. Not knowing that neutrons are used as nuclear projectiles because they have no charge — and writing protons instead — is a common nuclear physics error.

About Unnati Education

Unnati Education has been supporting NIOS students since 2010 and we understand exactly what NIOS Physics 312 demands in terms of exam preparation. We have built a complete chapter-wise objective question booklet covering all 30 lessons across all 8 modules with correct answers, step-by-step working, and clear explanations. We also provide solved TMAs, previous year question papers with complete solutions, and module-wise formula notes — all updated for both the April and October 2026 NIOS exam cycles.

How to Get the Complete Solutions

If you want the full NIOS Class 12 Physics 312 important questions booklet with complete solutions for 2026, or if you need previous year question papers, solved TMAs, or formula-wise notes for any module, contact Unnati Education today.

Phone and WhatsApp: 9654279279 or 9899436384 Website: unnatieducations.com/nios

Important Questions for NIOS Physics Class 12

Q1. Are these NIOS Class 12 Physics 312 important questions enough for the 2026 exam?

These chapter-wise questions cover the most important objective topics from all 8 modules and 30 lessons of NIOS Physics 312. They are a focused and reliable preparation resource for 2026. For the complete solution booklet with answers and full working for every chapter, contact Unnati Education and get your copy without delay.

Q2. Where can I get or download the NIOS Physics 312 important questions PDF for 2026?

Unnati Education provides a complete NIOS Physics 312 important questions PDF with MCQs, fill in the blanks, and true or false questions from all chapters with full answers and step-by-step solutions. contact our team will share the complete material with you quickly and directly without any waiting involved.

Q3. Does the booklet include numerical and formula-based questions from all Physics 312 modules?

Yes, the Unnati Education booklet for NIOS Physics 312 covers objective questions from all 8 modules including numerical questions from electricity, optics, thermodynamics, and mechanics. Every question has a correct answer with clear working. Contact us at 9654279279 or 9899436384 to get your complete 2026 solution booklet today.

Q4. Can I get previous year question papers for NIOS Physics 312 from Unnati Education?

Yes, Unnati Education provides previous year question papers with complete solutions for NIOS Physics 312. These papers show how questions are framed, which chapters carry more weight, and what level of calculation the exam expects across all modules. contact Unnati Education to get the full paper set for the 2026 exam cycle.

Q5. Is the Unnati Education booklet valid for both April and October 2026 NIOS Physics exams?

Yes, the Unnati Education objective question booklet for NIOS Physics 312 is fully valid for both the April and October 2026 NIOS exam cycles. All content is based on the current NIOS syllabus and is reviewed and updated throughout the year. Whichever exam cycle you are appearing in, this booklet prepares you completely for the objective section.