Physics · Class 12 Science

Nagaland Nbse Class 12 Physics — Real Previous-Year Papers

with complete answers

Real previous-year board papers, year by year — the official exam pattern, the full question paper, and every question solved the concept-first way. Distinct from the chapter-wise textbook bank.

2016–2025
Years of papers: 10
Total Papers: 10
Real Board Papers: 0
Sample papers: 308
Real-paper Q & A: 0
Sample-paper Q & A

Real board-paper questions available, by year

34 Q2025complete

34 Q2024complete

30 Q2023complete

30 Q2022complete

30 Q2021complete

30 Q2020complete

30 Q2019complete

30 Q2018complete

30 Q2017complete

30 Q2016complete

Nagaland Board of School Education 2025 · Set ANNUAL

Real board examination

About this paper

The real Class-12 board examination held in 2025. Every question below is solved the concept-first way. Sample papers are labelled honestly — never shown as a past exam.

Total marks: 70
Questions: 34
Duration: 180 min
Sections: 1

The marks / questions / duration above are the official exam pattern. We currently have 34 of this paper’s questions (100% of the full paper), with 34 fully solved. Questions we couldn’t yet extract or verify are held — never shown as complete.

Sections & marks

Section	Type	Questions	Marks each	Total
ASection A	compulsory	34	—	—
Total		34		70

The question paper

The questions we hold for this paper, laid out by section. Solutions are on the Answers tab.

Board Examination

Physics

Nagaland Board of School Education 2025 · Set ANNUAL

Series/Set: ANNUALRoll No. ________

Time Allowed: 3 hoursMaximum Marks: 70

General Instructions

This question paper contains 34 questions divided into 1 sections — A.
Section A comprises 34 questions (compulsory).

Above is the official exam pattern. The questions printed below are those we currently hold for this paper.

Section A

compulsory · 16 of 34 shown

Q1.

If both the charges and distance between them is doubled, then the new electrostatic force will be

(a) F
(b) 2F
(c) 3F
(d) 4F

[1]

Q2.

The maximum current that can be drawn from a cell is when

(a) R = 0
(b) r = 0
(c) R > r
(d) r > R

[1]

Q3.

A bar magnet of magnetic moment M is cut into two parts of equal lengths. The magnetic moment and pole strength of either part is

(a) $\frac{M}{2}, \frac{m}{2}$
(b) $M, \frac{m}{2}$
(c) $\frac{M}{2}, m$
(d) $M, m$

[1]

Q4.

A magnetic field of flux density 1.0 Wbm⁻² acts normal to a 80 turn coil of 0.01m² area. If this coil is removed from the field in 0.1s. The emf induced is

(a) 6V
(b) 7V
(c) 8V
(d) 9V.

[1]

Q5.

Which of the following rays is not an electromagnetic wave?

(a) Gamma rays
(b) X-rays
(c) Microwaves
(d) Beta rays.

[1]

Q6.

If the critical angle for total internal reflection from a medium to vacuum is 30°, then velocity of light in medium is (velocity of light = 3×10⁸ ms⁻¹).

(a) 1.5 × 10⁸ ms⁻¹
(b) 0.75 × 10⁸ ms⁻¹
(c) 3 × 10⁸ ms⁻¹
(d) 2 × 10⁸ ms⁻¹.

[1]

Page 1 of 6

Q7.

When a photon is accelerated (from rest) through a potential difference of one volt, the kinetic energy gained by it is equal to (a) 1837eV (b) 1 eV (c) (1)/(1837) eV (d) none of the above.

[1]

Q8.

Rutherford’s model of the atom was unstable, because (a) nuclei will break down (b) electrons move in circular orbits (c) orbiting electrons radiate energy (d) electrons are repelled by nucleus.

[1]

Q9.

A transistor has an current gain of 0.95. If the change in emitter current is 100 mA, then the change in the collector current is (a) 95 mA (b) 99.05 mA (c) 100.95 mA (d) 100 mA.

[1]

Q10.

In a communication system, noise is most likely to affect the signal in the (a) transmission medium (b) transmitter (c) information source (d) destination.

[1]

Q11.

The test charge used to measure electric field at a point should be vanishingly small. Why?

[1]

Q12.

A current of 5.0 A flows through a press of resistance 11Ω. Calculate the energy consumed by the press in 5 minutes.

[1]

Q13.

Name two useful devices based on the phenomenon of mutual induction.

[1]

Q14.

Define impact parameter.

[1]

Q15.

What type of feedback is required in an oscillator. Why?

[1]

Q16.

Define sky wave propagation.

[1]

Page 2 of 6

Section B

Q1.

A long wire carries a steady current. It is bent into a circle of one turn and the magnetic field at the centre of the coil is B. It is then bent into a circular loop of 'n' turns. Find the new magnetic field at the centre of the coil.

[2]

Q2.

Deduce an expression to show that an atom behaves as a magnetic dipole.

[2]

Q3.

Show that the displacement current produced is equal to the conduction current, when a capacitor is discharged. **OR** State the principle of production of electromagnetic waves. What is the value of velocity of these waves?

[2]

Q4.

The radius of oxygen nuclei (₈O¹⁶) is 2.8 × 10⁻¹⁵ m. Calculate the radius of the lead nucleus (₈₂Pb²⁰⁵). **OR** Find out the binding energy per nucleon of an α-particle in MeV. The masses of α-particle, proton and neutron are 4.00150 u, 1.00728 u and 1.00867 u respectively.

[2]

Q5.

How does the potential barrier change, when a p-n junction is reverse biased? Can the potential barrier be measured by putting a sensitive voltmeter across its terminal?

[2]

Q6.

Which is the basic mode of communication used in satellite communication? Write the expression for the maximum line of sight with distance 'd' between two antennae having heights h₁ and h₂.

[2]

Page 3 of 6

Section C

Q1.

Two point charges q₁ = 3 μC and q₂ = −3μC are located 20cm apart in vacuum. i) What is the electric field at the mid-point of the line joining the two charges? ii) If a test charge of magnitude 1.5 × 10⁻⁹C is placed at this point, what is the force experienced by this charge? **OR** Find the equivalent capacitance of the capacitors in the network shown below. Also, calculate the total charge in the network when a 100V battery is connected across the combination. Given that C₁=C₅= 1 μF, C₂=C₃=C₄ =2 μF.

[3]

Q2.

Find the expression of resistivity of a conductor in terms of relaxation time. What is the effect of temperature on the resistivity? **OR** Using Kirchoff's rules, deduce the balanced condition of a Wheatstone bridge. Name a practical device where Wheatstone bridge principle is applied.

[3]

Q3.

Using Ampere circuital law, find the magnitude of magnetic field along the axis of a current carrying solenoid. What kind of magnetic field is produced due to a straight solenoid? **OR** A rectangular coil of N turns having area A is placed in a uniform magnetic field B. The coil makes an angle θ with respect to the direction of the field. When current I is passed to the coil, a torque acts on it. Find the magnitude of torque acting on the coil.

[3]

Q4.

Find the induced emf developed in a conductor of length 'l' moving with velocity V in transverse magnetic field of strength B. What factors governs the direction of emf?

[3]

Q5.

A double convex lens has 10 cm and 15 cm as its two radii of curvature. The image of an object, placed 30 cm from the lens, is formed at 20 cm from the lens on the other side. Find the refractive index of the material of the lens. What will be the focal length? What will be the focal length of the lens if it is immersed in water of refractive index 1.33?

[3]

Page 4 of 6

Q6.

State two essential conditions, which must be satisfied for two light sources to be coherent. Two light waves of amplitudes a₁ and a₂ interfere with each other. Show that fracImaxImin = ((a₁+a₂)/(a₁-a₂))².

[3]

Q7.

Discuss de-Broglie concept of matter waves with the help of relevant expressions.

[3]

Q8.

Explain the energy level diagram of a hydrogen atom.

[3]

Q9.

With a circuit diagram, explain how a junction diode can act as a full-wave rectifier.

[3]

Section D

Q1.

Derive an expression for the electric field at a point on a perpendicular bisector of an electric dipole moment. If Eₐ and Eb are the electric field on the axial line and perpendicular bisector of dipole, then show Eₐ = 2Eb. Also, what is the direction of electric dipole moment vector of an electric dipole? **OR** State and prove Gauss theorem. Two infinite parallel planes have uniform charge densities ±σ. What is the electric field - i) in the region between the planes and ii) outside the plates?

[5]

Page 5 of 6

Q2.

Define alternating current and root mean square value of alternating current. Prove that Irms = fracIO√(2), where IO is peak value of current. **OR** Establish an expression for the average power in a LCR series circuit. Prove mathematically that the average power over a complete cycle of alternating current through an ideal inductor is zero. What is the value of power factor at resonance?

[5]

Q3.

Discuss the phenomenon of refraction through a prism and show that A + D = i + e, where the symbols have their usual meaning. Also, find the refractive index of the material of prism at minimum deviation position.

[5]

Page 6 of 6