The CBSE Class 12 Physics Question Paper 2026 Set 3 is available for download here of CBSE Board Exam 2026. This CBSE 12th Physics solved question paper includes detailed solutions, answer key, and the latest CBSE marking scheme to help students understand the exam pattern and important topics.

By practicing the CBSE Class 12 Physics 2026 board exam paper PDF, students can improve answer-writing strategy, time management, and overall exam performance.

CBSE Class 12 Physics Question PDF Solution PDF
Set 1 55-1-1 Download PDF View Solution
Set 2 55 1 2 Download PDF View Solution
Set 3 55 1 3 Download PDF View Solution
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Set 1 55 4 1 Download PDF View Solution
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CBSE Class 12 Physics Question Paper 2026 Set 3 55-5-3

CBSE Class 12 Physics Question Paper 2026 Set 3 55-5-3 Download PDF Check Solutions

Question 1:

A 500 nm photon is incident normally on a perfectly reflecting surface and is reflected. The value of momentum transferred to the surface is:

  • (A) \( 3.87 \times 10^{-43} \, kg \, ms^{-1} \)
  • (B) \( 2.5 \times 10^{-30} \, kg \, ms^{-1} \)
  • (C) \( 2.65 \times 10^{-27} \, kg \, ms^{-1} \)
  • (D) \( 1.33 \times 10^{-27} \, kg \, ms^{-1} \)

Question 2:

A good diode checked by a multimeter should indicate:

  • (A) high resistance in reverse bias and a low resistance in forward bias
  • (B) high resistance in both forward bias and reverse bias
  • (C) low resistance in both reverse bias and forward bias
  • (D) high resistance in forward bias and low resistance in reverse bias

Question 3:

A square loop of side 0.50 m is placed in a uniform magnetic field of 0.4 T perpendicular to the plane of the loop. The loop is rotated through an angle of 60° in 0.2 s. The value of emf induced in the loop will be:

  • (A) 5 V
  • (B) 3.5 V
  • (C) 2.5 V
  • (D) Zero V

Question 4:

The magnetic field in a plane electromagnetic wave travelling in glass (n = 1.5) is given by: \[ B_y = (2 \times 10^{-7} \, T) \sin ( \alpha x + 1.5 \times 10^{11} t) \]
where x is in metres and t is in seconds. The value of \( \alpha \) is:

  • (A) \( 0.5 \times 10^3 \, m^{-1} \)
  • (B) \( 6.0 \times 10^2 \, m^{-1} \)
  • (C) \( 7.5 \times 10^2 \, m^{-1} \)
  • (D) \( 1.5 \times 10^3 \, m^{-1} \)

Question 5:

A charged particle is moving in a uniform magnetic field \( \vec{B} \) with a constant speed \( v \) in a circular path of radius \( r \). Which of the following graphs represents the variation of radius of the circle, with the magnitude of magnetic field \( \vec{B} \)?


Question 6:

Which of the following statements is not true for electric energy in ac form compared to that in dc form?

  • (A) Production of ac is economical.
  • (B) ac can be easily and efficiently converted from one voltage to another.
  • (C) ac can be transmitted economically over long distances.
  • (D) ac is less dangerous.

Question 7:

The energy of an electron in an orbit in hydrogen atom is -3.4 eV. Its angular momentum in the orbit will be:

  • (A) \( \frac{3h}{2\pi} \)
  • (B) \( \frac{2h}{\pi} \)
  • (C) \( \frac{h}{\pi} \)
  • (D) \( \frac{h}{2\pi} \)

Question 8:

The rms and the average value of an ac voltage \( V = V_0 \sin \omega t \) over a cycle respectively will be:

  • (A) \( \frac{V_0}{2}, \, \frac{V_0}{\sqrt{2}} \)
  • (B) \( \frac{V_0}{\pi}, \, \frac{V_0}{2} \)
  • (C) \( \frac{V_0}{\sqrt{2}}, \, 0 \)
  • (D) \( V_0, \, \frac{V_0}{\sqrt{2}} \)

Question 9:

The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be:

  • (A) \( \frac{q}{4 \pi \epsilon_0 l^2} \) pointing along MA
  • (B) \( \frac{q}{\pi \epsilon_0 l^2} \) pointing along AM
  • (C) \( \frac{q}{2 \pi \epsilon_0 l^2} \) pointing along AM
  • (D) Zero

Question 10:

Consider the nuclear reaction \( X \to Y + Z \). Let \( M_x \), \( M_y \), and \( M_z \) be the masses of the three nuclei X, Y, and Z respectively. Then which of the following relations hold true?

  • (A) \( (M_x - M_z) < M_y \)
  • (B) \( (M_x - M_y) < M_z \)
  • (C) \( M_x > (M_y + M_z) \)
  • (D) \( M_x < (M_y + M_z) \)

Question 11:

Two points R and S are equidistant from two charges \( +Q \) and \( -2Q \). The work done in moving a charge \( -Q \) from point R to S is:

  • (A) Zero
  • (B) \( - \frac{Q}{4 \pi \epsilon_0 d} \)
  • (C) \( \frac{Q}{4 \pi \epsilon_0 d} \)
  • (D) \( \frac{3Q}{4 \pi \epsilon_0 d} \)

Question 12:

The radius of a nucleus of mass number 125 is:

  • (A) 6.0 fm
  • (B) 30 fm
  • (C) 72 fm
  • (D) 150 fm

Question 13:

Assertion (A): In Young’s double-slit experiment, the fringe width for dark and bright fringes is the same.
Reason (R): Fringe width is given by \( \beta = \frac{\lambda D}{d} \), where symbols have their usual meanings.

  • (A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  • (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
  • (C) Assertion (A) is true, but Reason (R) is false.
  • (D) Both Assertion (A) and Reason (R) are false.

Question 14:

Assertion (A): Energy is released when heavy nuclei undergo fission or light nuclei undergo fusion.
Reason (R): For heavy nuclei, binding energy per nucleon increases with increasing \( Z \) while for light nuclei, it decreases with increasing \( Z \).

  • (A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  • (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
  • (C) Assertion (A) is true, but Reason (R) is false.
  • (D) Both Assertion (A) and Reason (R) are false.

Question 15:

A light copper ring is freely suspended by a light string. A bar magnet is held horizontally with its length along the axis of the ring. The magnet is moved towards the ring with its N pole facing the loop. What will happen to the ring and its position? Explain.


Question 16:

A ray of light MN is incident normally on the face corresponding with side AB of a prism with an isosceles right-angled triangular base ABC. Trace the path of the ray as it passes through the prism when the refractive index of the prism material is (i) \( \sqrt{2} \), and (ii) \( \sqrt{3} \).


Question 17:

When monochromatic light is incident on a surface separating two media, the refracted and reflected light both have the same frequency as the incident frequency but the wavelength of refracted light is different. Explain why.


Question 18:

Suppose a pure Si crystal has \( 5 \times 10^{28} \) atoms per \( m^3 \). It is doped with \( 5 \times 10^{22} \) atoms per \( m^3 \) of Arsenic. Calculate the majority and minority carrier concentration in the doped silicon. (Given: \( n_i = 1.5 \times 10^{16} \, m^{-3} \))


Question 19:

An electric iron rated 2.2 kW, 220 V is operated at 110 V supply.
Find:
[(i)] its resistance, and
[(ii)] heat produced by it in 10 minutes.


Question 20:

A current of 4.0 A flows through a wire of length 1 m and cross-sectional area \( 1.0 \, mm^2 \), when a potential difference of 2 V is applied across its ends.
Calculate the resistivity of the material of the wire.


Question 21:

What is meant by displacement current? A capacitor is being charged by a battery. Show that Ampere-Maxwell law justifies continuity and constancy of the current flowing in the circuit.


Question 22:

Can a transformer step up or step down dc power supply?


Question 23:

Can a step up transformer work as a step down transformer?


Question 24:

Does a step up transformer contradict the principle of conservation of energy? Justify your answer.


Question 25:

Draw a circuit diagram of a full-wave rectifier using p-n junction diodes. Explain its working and show the input-output waveforms.


Question 26:

Two point charges \(q_1 = 2.5 \times 10^{-7}\) C and \(q_2 = -2.5 \times 10^{-7}\) C are located at points (0, 0, -15 cm) and (0, 0, 15 cm) respectively. Find: (a) the electric dipole moment of the system, and (b) the magnitude and direction of electric field at the origin (0, 0, 0).


Question 27:

Photoemission of electrons occurs from a metal (\(\phi_0 = 1.96\) eV) when light of frequency \(6.4 \times 10^{14}\) Hz is incident on it. Calculate: (a) Energy of a photon in the incident light, (b) The maximum kinetic energy of the emitted electrons, and (c) The stopping potential.


Question 28:

Write any two features of nuclear forces.


Question 29:

If both the number of protons and the neutrons are conserved in each nuclear reaction, in what way is mass converted into energy (or vice versa) in a nuclear reaction? Explain.


Question 30:

Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.


Question 31:

If Bohr’s quantization postulate (angular momentum = \(\frac{nh}{2\pi}\)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.


Question 32:

Write the expression for the magnetic field due to a current element in vector form. Consider a 1 cm segment of a wire, centered at the origin, carrying a current of 10 A in positive x-direction. Calculate the magnetic field \(\vec{B}\) at a point (1 m, 1 m, 0).


Question 33:

The electric field \(\vec{E}\) in the region between the plates is:

  • (A) \(\left( 2 \times 10^2 \, \frac{V}{m} \right) \hat{k}\)
  • (B) \(-\left( 2 \times 10^2 \, \frac{V}{m} \right) \hat{k}\)
  • (C) \(\left( 2 \times 10^4 \, \frac{V}{m} \right) \hat{k}\)
  • (D) \(-\left( 2 \times 10^4 \, \frac{V}{m} \right) \hat{k}\)

Question 34:

In the region between the plates, the electron moves with an acceleration \(\vec{a}\) given by:

  • (A) \(- (3.5 \times 10^{15} \, ms^{-2}) \, \hat{k}\)
  • (B) \((3.5 \times 10^{15} \, ms^{-2})\, \hat{k}\)
  • (C) \((3.5 \times 10^{13} \, ms^{-2})\, \hat{i}\)
  • (D) \(- (3.5 \times 10^{13} \, ms^{-2}) \, \hat{i}\)

Question 35:

Time interval during which an electron moves through the region between the plates is:

  • (A) \( 9.0 \times 10^{-9} \, s \)
  • (B) \( 1.67 \times 10^{-8} \, s \)
  • (C) \( 1.67 \times 10^{-9} \, s \)
  • (D) \( 2.17 \times 10^{-9} \, s \)

Question 36:

The vertical displacement of the electron which travels through the region between the plates is:

  • (A) 10 mm
  • (B) 4.9 mm
  • (C) 5.9 mm
  • (D) 3.0 mm

Question 37:

What property of light does this interference experiment demonstrate?

  • (A) Wave nature of light
  • (B) Particle nature of light
  • (C) Transverse nature of light
  • (D) Both wave nature and transverse nature of light

Question 38:

The wavelength of light used in this experiment is:

  • (A) 720 nm
  • (B) 590 nm
  • (C) 480 nm
  • (D) 364 nm

Question 39:

The fringe width in the interference pattern formed on the screen is:

  • (A) 1.2 mm
  • (B) 0.2 mm
  • (C) 4.2 mm
  • (D) 6.8 mm

Question 40:

The path difference between the two waves meeting at point P, where there is a minimum in the interference pattern is:

  • (A) \( 8.1 \times 10^{-7} \, m \)
  • (B) \( 7.2 \times 10^{-7} \, m \)
  • (C) \( 6.5 \times 10^{-7} \, m \)
  • (D) \( 6.0 \times 10^{-7} \, m \)

Question 41:

When the experiment is performed in a liquid of refractive index greater than 1, then fringe pattern will:

  • (A) disappear
  • (B) become blurred
  • (C) be widened
  • (D) be compressed

Question 42:

A parallel beam of monochromatic light falls normally on a single slit of width 'a' and a diffraction pattern is observed on a screen placed at distance D from the slits. Explain:
(I) the formation of maxima and minima in the diffraction pattern, and
(II) why the maxima go on becoming weaker and weaker with its increasing number (n).


Question 43:

Write any two points of difference between interference pattern due to double-slit and diffraction pattern due to single-slit.


Question 44:

With the help of a ray diagram, describe the construction and working of a compound microscope.


Question 45:

The real image of an object placed between f and 2f from a convex lens can be seen on a screen placed at the image location. If the screen is removed, is the image still there? Explain.


Question 46:

Plane and convex mirrors produce virtual images of objects. Can they produce real images under some circumstances? Explain.


Question 47:

Derive the condition for which a Wheatstone Bridge is balanced.


Question 48:

Consider a cylindrical conductor of length \( l \) and area of cross-section A. Current I is maintained in the conductor and electrons drift with velocity \( v_d \) (\( |v_d| = \frac{e|E|}{m} \tau \)), (where symbols have their usual meanings). Show that the conductivity \( \sigma \) of the material of the conductor is given by
\[\sigma = \frac{ne^2}{m} \tau.\]


Question 49:

The resistance of a metal wire at 20°C is 1.05 Ω and at 100°C is 1.38 Ω. Determine the temperature coefficient of resistivity of this metal.


Question 50:

A rectangular loop of sides a and b carrying current I is placed in a magnetic field B such that its area vector A makes an angle θ with B. With the help of a suitable diagram, show that the torque \(\vec{\tau}\) acting on the loop is given by \(\vec{\tau} = \vec{m} \times \vec{B}\), where \(\vec{m}\) (\(\equiv \vec{I} \times \vec{A}\)) is the magnetic dipole moment of the loop.


Question 51:

A circular coil of 100 turns and radius \(\left(\frac{10}{\sqrt{\pi}}\right)\) cm carrying current of 5.0 A is suspended vertically in a uniform horizontal magnetic field of 2.0 T. The field makes an angle \(30^\circ\) with the normal to the coil. Calculate:
(I) the magnetic dipole moment of the coil, and
(II) the magnitude of the counter torque that must be applied to prevent the coil from turning.


Question 52:

Derive an expression for the force \(\vec{F}\) acting on a conductor of length \(L\) and area of cross-section \(A\) carrying current \(I\) and placed in a magnetic field \(\vec{B}\).


Question 53:

A part of a wire carrying 2.0 A current and bent at 90° at two points is placed in a region of uniform magnetic field \(\vec{B} = - (0.50 \, T) \, \hat{k}\), as shown in the figure. Calculate the magnitude of the net force acting on the wire.

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