NEB Grade XII Physics 2083 (2026) Set E — Question Paper, Answer Key & Complete Guide
This article covers the complete NEB Grade XII Physics 2083 (2026) Set E question paper (Sub.Code 1021’E’), including the MCQ answer key, full question paper for download/reference, important questions likely to repeat in future exams, FAQs, and a detailed chapter-wise preparation guide.
Quick Navigation
- MCQ Answer Key
- Full Question Paper (Group A, B, C)
- Important Questions for Future Exams
- FAQs Exam Pattern & Chapter-wise Weightage
- Preparation Strategy
MCQ Answer Key — NEB Physics 2083 Set E
Here are the correct answers to all 11 MCQs (Group A) from the 1021’E’ Physics paper, with the marking scheme of 1 mark each (Total: 11 marks).
| Q. No. | Topic | Correct Answer |
|---|---|---|
| 1 | Factor affecting radius of gyration | B) Axis of rotation |
| 2 | % increase in pendulum period (L increased by 21%) | B) 10% |
| 3 | Cork rising and floating — v-t graph | D |
| 4 | Petrol vs diesel engine efficiency | C) η₁ < η₂ |
| 5 | Thermodynamic process with minimum work done | D) Isochoric |
| 6 | Distance between node and antinode | B) λ/4 |
| 7 | Time for light to cross 5 cm glass slab (n=1.5) | B) 0.25 ns |
| 8 | EMF from temperature difference at junctions | A) Seebeck effect |
| 9 | Portion representing coercivity (hysteresis loop) | D) AE |
| 10 | Impedance (R=8Ω, XL=6Ω) | C) 10Ω |
| 11 | Function of diode as rectifier | D) ac into dc |
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Quick working for tricky ones: Q2 — T = 2π√(L/g); L→1.21L gives T→1.1T, so period increases by 10%. Q7 — speed in glass = c/n = 2×10⁸ m/s; time = 0.05/(2×10⁸) = 0.25 ns. Q10 — Z = √(8² + 6²) = √100 = 10Ω (a 6-8-10 triple).
Full Question Paper
Important Questions Likely to Repeat in Future NEB Exams
Based on the 2083 pattern and historical repetition across NEB Physics sets, these topics deserve priority preparation:
- Derive Cₚ – C_V = R using the first law of thermodynamics
- Doppler effect: frequency heard as a source approaches and recedes
- Young’s double slit: derive fringe width and show equal spacing of fringes
- Conservation of angular momentum — why Earth speeds up near the Sun
- Lenz’s law and the falling magnet through a metal ring problem
- Half-life and decay constant from a radioactive decay graph
- Magnetic field on the axial line of a current-carrying circular coil
- AC circuits: inductor voltage leading current by π/2, with phasor diagram
- Diffraction grating: spacing, angle of maxima, number of orders
- Einstein’s photoelectric equation; Planck’s constant from a Kmax-frequency graph
- Full-wave rectifier using two P-N junction diodes
- Stoke’s law and derivation of coefficient of viscosity
Frequently Asked Questions
What is the correct answer for Q1 — factor affecting radius of gyration?
The answer is B) Axis of rotation. Radius of gyration (k) depends on how mass is distributed relative to the chosen axis — change the axis, and k changes. Angular speed, angular acceleration, and g have no effect on k.
How is the 10% answer obtained for Q2 (pendulum length increased by 21%)?
T = 2π√(L/g). If L becomes 1.21L, then T becomes √1.21 × T = 1.1T. So the period increases by 10% — that’s the trick behind choosing 21% specifically (since √1.21 = 1.1).
Which thermodynamic process has zero/minimum work done, and why?
Isochoric (constant volume). Work done W = PΔV; since ΔV = 0, no work is done. This makes it the minimum among all four standard processes.
What is the node-to-antinode distance in a stationary wave?
λ/4. Nodes repeat every λ/2, and antinodes sit exactly midway between consecutive nodes — so the gap from a node to its nearest antinode is half of λ/2, i.e., λ/4.
How do you solve Q7 (time for light to cross a glass slab)?
Speed of light in glass = c/n = (3×10⁸)/1.5 = 2×10⁸ m/s. Time = distance/speed = 0.05 m ÷ (2×10⁸ m/s) = 0.25 ns.
Which segment of the hysteresis loop represents coercivity?
Coercivity is the reverse field needed to bring residual magnetization (B) to zero after the material was magnetized. On the given loop, this corresponds to segment AE on the −H axis.
How do you calculate impedance for Q10?
Z = √(R² + X_L²) = √(8² + 6²) = √100 = 10Ω — a classic 6-8-10 Pythagorean triple.
How do you solve the Doppler effect numerical in Q15(b)?
Approaching: f₁ = f × v/(v − vₛ) = 500 × 340/320 ≈ 531.25 Hz. Receding: f₂ = 500 × 340/360 ≈ 472.22 Hz. Change in frequency ≈ 59 Hz.
Is the organ pipe in Q20(c) open or closed?
Closed. The frequencies 200, 600, 1000 Hz are in the ratio 1:3:5 — only odd harmonics, which is the signature of a closed organ pipe with fundamental 200 Hz.
How do you find the force per unit length in Q22(d)?
F/L = μ₀I₁I₂/(2πd) = (4π×10⁻⁷ × 3 × 2)/(2π × 0.1) = 1.2×10⁻⁵ N/m, attractive (currents in the same direction).
Exam Pattern & Chapter-wise Weightage
The 2083 Set E paper distributes its 75 marks across three groups: Group A (11 MCQs, 1 mark each = 11 marks), Group B (8 short-answer questions, 5 marks each = 40 marks), and Group C (3 long-answer questions, 8 marks each = 24 marks). Several questions in Groups B and C offer OR alternatives, giving students a choice between two chapters.
| Group | Type | Questions | Marks Each | Total |
|---|---|---|---|---|
| A | MCQ | 11 | 1 | 11 |
| B | Short Answer | 8 (some with OR) | 5 | 40 |
| C | Long Answer | 3 (some with OR) | 8 | 24 |
| Total | 75 |
Preparation Strategy for NEB Physics
Master the standard derivations. Cₚ − C_V = R, Laplace’s correction, the magnetic field of a circular coil, and Young’s double slit fringe width appear in nearly every NEB set — practice writing each from memory at least three times.
Practice graph-based questions. This paper alone has graphs in Q3, Q16, Q18, and Q21. Get comfortable reading hysteresis loops, resistivity-temperature curves, radioactive decay graphs, and photoelectric Kmax-frequency plots.
Drill these five numerical types: Doppler effect, rotational kinetic energy/angular momentum, heat engine efficiency, potentiometer/potential gradient, and force between parallel conductors. All five recur year after year.
Don’t skip the OR options. Q13, Q17, Q20, and Q21 each offer an alternative. Know both sides well enough to choose confidently on exam day rather than getting stuck.
Conceptual MCQs matter. Six of the eleven MCQs in this paper are pure concept, no calculation — know definitions like Seebeck effect, coercivity, and what a rectifier does cold.
Manage your three hours wisely. A reasonable split: Group C (45 min), Group B (90 min), MCQs (20 min), and a final revision pass (25 min). Tackling Group C first while you’re fresh tends to maximize long-answer scores.
Conclusion
The NEB Grade XII Physics 2083 Set E paper rewards students who’ve practiced derivations, solved standard numericals, and can read graphs confidently — particularly in Electromagnetism, Optics, and Modern Physics. The presence of graph-based questions across four different sections signals that NEB increasingly values analytical thinking over memorization. Use this paper as a timed practice test: attempt it in 3 hours, then check your work against the answer key and explanations above.