Physics · 2022 · Set 55/1/1

CBSE Class 12 Physics 2022 — Set 55/1/1

CBSE Class XII Board 2022 · Set 55/1/1

Real board examination

Sets

About the 2022 exam: 2022 was CBSE's special COVID year: the board exam was split into two terms instead of one 70-mark paper. Term 1 (Dec 2021) was multiple-choice only; Term 2 (2022 — the papers shown here) was a shorter subjective paper of just 12 questions for 35 marks. So the smaller size IS the real exam that year, not missing content — 3 complete series (55/1/1, 55/2/1, 55/4/1) of 12 questions each. Some topics examined then have since been removed from the syllabus — badged and filterable above.

This paper has 1 question on a topic removed in CBSE’s 2023-24 syllabus update (each marked Not in syllabus). It’s kept for historical accuracy — the exam really asked it that year — but isn’t in the current syllabus and doesn’t count toward a concept’s importance. Switch to to focus on what’s still examinable.

About this paper

The real Class-12 board examination held in 2022. Every question below is solved the concept-first way. Sample papers are labelled honestly — never shown as a past exam.

Total marks: 35
Questions: 12
Duration: 120 min
Sections: 3

The marks / questions / duration above are the official exam pattern. We currently have 12 of this paper’s questions (100% of the full paper), with 12 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	Short answer	3	2	6
BSection B	Short answer	8	3	24
CSection C	Case-based	1	5	5
Total		12		35

The question paper

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

Board Examination

Physics

CBSE Class XII Board 2022 · Set 55/1/1

Series/Set: 55/1/1Roll No. ________

Time Allowed: 2 hoursMaximum Marks: 35

General Instructions

This question paper contains 12 questions divided into 3 sections — A, B, C.
Section A comprises 3 questions of 2 marks each (Short answer).
Section B comprises 8 questions of 3 marks each (Short answer).
Section C comprises 1 question of 5 marks each (Case-based).

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

Section A

Short answer · 2 marks each · 3 of 3 shown

Q1.

Draw energy band diagrams of n-type and p-type semiconductors at temperature

T > 0\,\text{K}

, depicting the donor and acceptor energy levels. Mention the significance of these levels.

[2]

Q2.

(a) Draw the graph showing the variation of the number

(N)

of scattered alpha particles with scattering angle

(\theta)

in Geiger-Marsden experiment. Infer two conclusions from the graph.

(OR)

(b) Plot suitable graphs to show the variation of photoelectric current with the collector plate potential for the incident radiation of

(i) the same intensity but different frequencies $\nu_1$ , $\nu_2$ and $\nu_3$ $(\nu_1 < \nu_2 < \nu_3)$
(ii) the same frequency but different intensities $I_1$ , $I_2$ and $I_3$ $(I_1 < I_2 < I_3)$

[2]

Q3.

Write the characteristics of a p-n junction which make it suitable for rectification.

[2]

Section B

Short answer · 3 marks each · 8 of 8 shown

Q1.

Define the term - Distance of closest approach. How will it be affected, for an

\alpha

-particle, if kinetic energy of the particle is doubled?

[3]

Page 1 of 3

Q2.

A point source in air is kept 24 cm in front of a concave spherical glass surface (aμg = 1.5) and radius of curvature 60 cm. Find the nature of the image formed and its distance from the point source.

[3]

Q3.

Calculate the energy released in MeV in the following reaction: ²₁H + ³₁H longrightarrow ⁴₂He + n Given: m(²₁H) = 2.014102u, m(³₁H) = 3.016049u, m(⁴₂He) = 4.002603u, mₙ = 1.008665u.

[3]

Q4.

Explain with the help of a suitable diagram, the phenomenon on which an optical fibre works. Mention any two uses of optical fibres.

[3]

Q5.

(a) A parallel beam of light of wavelength 600 nm is incident normally on a slit of width 0.2 mm. If the resulting diffraction pattern is observed on a screen 1 m away, find the distance of (i) first minimum, and (ii) second maximum, from the central maximum. OR (b) A thin equiconvex lens of radius of curvature R made of material of refractive index μ₁ is kept coaxially, in contact with an equiconcave lens of the same radius of curvature and refractive index μ₂ (>μ₁). Find: (i) the ratio of their powers, and (ii) the power of the combination and its nature.

[3]

Q6.

Photoelectrons are emitted from a metal surface when illuminated with UV light of wavelength 330 nm. The minimum amount of energy required to emit the electrons from the surface is 3.5 × 10⁻¹⁹J. Calculate: (i) the energy of the incident radiation, and (ii) the kinetic energy of the photoelectron.

[3]

Q7.

State the working principle of an LED. Write any two important advantages and two disadvantages of LED.

⚠ This question is not in the current syllabus — special-purpose p-n junction diodes (LED) (removed 2023-24)

[3]

Page 2 of 3

Q8.

(a) (i) Monochromatic light is incident on a surface separating two media. The frequency of the light after refraction remains unaffected but its wavelength changes. Why? (ii) The frequency of an electromagnetic radiation is 1.0 × 10¹¹Hz. Identify the radiation and mention its two uses. OR (b) (i) Trace the path of a ray of light PQ which is incident at an angle i on one face of a glass prism of angle A. It then emerges out from the other face at an angle e. Use the ray diagram to prove that the angle through which the ray is deviated is given by ∠δ = ∠ i + ∠ e - ∠ A. (ii) What will be the minimum value of δ if the ray passes symmetrically through the prism?

[3]

Section C

Case-based · 5 marks each · 1 of 1 shown

Q1.

The principle of superposition is used to understand the phenomenon of interference of light waves. The principle states that at a particular point, the resultant displacement produced by a number of waves is the vector sum of the displacements produced by each wave. Light waves from two coherent sources produce interference pattern. Thomas Young devised a way to obtain two coherent sources using two identical pinholes (S₁ and S₂) illuminated by a single monochromatic pinhole source S. Using these sources in his experiment known as Young's double slit experiment, Young studied the interference pattern. The pattern consists of alternate bright and dark fringes. The distance between two successive bright or dark fringes depends on the distance between S₁ and S₂, the distance of the screen from the plane of S₁ S₂ and the wavelength of light used. I. Consider the following waves: (i) y₁ = a sin ω t (ii) y₂ = a sin 2ω t (iii) y₃ = a sin (2ω t + φ) (iv) y₄ = a sin (4ω t + (π)/(2)) Which pair of the waves coming from two sources S₁ and S₂ will produce interference? (A) (i) and (ii) (B) (ii) and (iii) (C) (iii) and (iv) (D) (iv) and (i) II. Two light waves of the same intensity I₀ each, having a path difference of λ/4, emanating from two coherent sources, meet at a point. The resultant intensity at the point will be (A) Zero (B) I₀ (C) 2I₀ (D) 4I₀ III. Vandana performs Young's double slit experiment by using orange, green and red lights successively. If the fringe widths measured in the three cases are ω₁, ω₂ and ω₃ respectively, then which of the following is correct? (A) ω₂ > ω₁ > ω₃ (B) ω₁ > ω₂ > ω₃ (C) ω₂ > ω₃ > ω₁ (D) ω₃ > ω₁ > ω₂ IV. In a Young's double slit experiment, the slit separation is 0.8 mm and the interference pattern is obtained on a screen kept 50 cm from the plane of the slits S₁ and S₂. If the first bright fringe is formed 0.4 mm from the central maximum, the wavelength of light used is (A) 480 nm (B) 560 nm (C) 640 nm (D) 680 nm V. Consider the effect on the angular separation of the fringes in a Young's double slit experiment due to the following operations: (i) the screen is moved away from the plane of the slits, (ii) the separation between the two slits is increased till fringes are observed. Which of the following options is correct? (A) It remains constant in both cases. (B) It decreases in both cases. (C) It remains constant in (i) but decreases in (ii). (D) It decreases in (i) but remains constant in (ii).

[5]

Page 3 of 3