CBSE Class 12 Physics 2022 question paper (55/1)

Maximum marks 35 · Time 2 hours · 3 sets

Try each question first, then open its model answer. Where the paper offers a choice, both questions are shown with OR between them.

Section A

2 marks each

Q.12 marks $T > 0\,\mathrm{K}$
Q.2 (a)2 marks $(\theta)$
OR
Q.2 (b)2 marks $\nu_1$
Q.32 marks $Write the characteristics of a p-n junction which make it suitable for rectification.$

Section B

3 marks each

Q.43 marks $\alpha$
Q.53 marks $({}_{a}\mu_{g} = 1.5)$
Q.63 marks ${}^{2}_{1}\mathrm{H} + {}^{3}_{1}\mathrm{H} \longrightarrow {}^{4}_{2}\mathrm{He} + \mathrm{n}$
Q.73 marks $Explain with the help of a suitable diagram, the phenomenon on which an optical fibre works. Mention any two uses of optical fibres.$
Q.8 (a)3 marks $A parallel beam of light of wavelength 600 nm is incident normally on a slit of width 0.2 mm. If the resulting diffraction pattern is observed on a screen 1 m away, find the distance of (i) first minimum, and (ii) second maximum, from the central maximum.$
OR
Q.8 (b)3 marks $\mu_1$
Q.93 marks $3.5 \times 10^{-19}$
Q.103 marks $State the working principle of an LED. Write any two important advantages and two disadvantages of LED.$
Q.11 (a)3 marks $1.0 \times 10^{11}$
OR
Q.11 (b)3 marks $\angle\delta = \angle i + \angle e - \angle A$

Section C

1 mark each

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 ( $S_1$ and $S_2$ ) 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 finges depends on the distance between $S_1$ and $S_2$ , the distance of the screen from the plane of $S_1S_2$ and the wavelength of light used.
Q.12 (I)1 mark $y_1 = a \sin \omega t$
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Q.12 (II)1 mark $I_0$
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Q.12 (III)1 mark $\omega_1$
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Q.12 (IV)1 mark $S_1$
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Q.12 (V)1 mark $Consider the effect on the angular separation of the fringes in a Young's double slit experiment due to the following operations : (i) the screen is moved away from the plane of the slits, (ii) the separation between the two slits is increased till fringes are observed. Which of the following options is correct ?$
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Section A

2 marks each

Q.12 marks $Explain the formation of depletion layer and barrier potential in a p-n junction diode.$
Q.22 marks $T > 0\,\mathrm{K}$
Q.3 (a)2 marks $(\theta)$
OR
Q.3 (b)2 marks $\nu_1$

Section B

3 marks each

Q.43 marks $Explain with the help of a suitable diagram, the phenomenon on which an optical fibre works. Mention any two uses of optical fibres.$
Q.53 marks $-2.5$
Q.6 (a)3 marks $A parallel beam of light of wavelength 600 nm is incident normally on a slit of width 0.2 mm. If the resulting diffraction pattern is observed on a screen 1 m away, find the distance of (i) first minimum, and (ii) second maximum, from the central maximum.$
OR
Q.6 (b)3 marks $\mu_1$
Q.7 (a)3 marks $1.0 \times 10^{11}$
OR
Q.7 (b)3 marks $\angle\delta = \angle i + \angle e - \angle A$
Q.83 marks $State the working principle of an LED. Write any two important advantages and two disadvantages of LED.$
Q.93 marks $(a) Sketch the energy level diagram for hydrogen atom. (b) Find the ratio of the longest and the shortest wavelength in Lyman series in hydrogen atom.$
Q.103 marks $+5.0$
Q.113 marks ${}^{2}_{1}\mathrm{H} + {}^{3}_{1}\mathrm{H} \longrightarrow {}^{4}_{2}\mathrm{He} + \mathrm{n}$

Section C

1 mark each

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 ( $S_1$ and $S_2$ ) 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 finges depends on the distance between $S_1$ and $S_2$ , the distance of the screen from the plane of $S_1S_2$ and the wavelength of light used.
Q.12 (I)1 mark $y_1 = a \sin \omega t$
Tap an option to check your answer.
Q.12 (II)1 mark $I_0$
Tap an option to check your answer.
Q.12 (III)1 mark $\omega_1$
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Q.12 (IV)1 mark $S_1$
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Q.12 (V)1 mark $Consider the effect on the angular separation of the fringes in a Young's double slit experiment due to the following operations : (i) the screen is moved away from the plane of the slits, (ii) the separation between the two slits is increased till fringes are observed. Which of the following options is correct ?$
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Section A

2 marks each

Q.1 (a)2 marks $(\theta)$
OR
Q.1 (b)2 marks $\nu_1$
Q.22 marks $n_e \neq n_h$
Q.32 marks $T > 0\,\mathrm{K}$

Section B

3 marks each

Q.4 (a)3 marks $A parallel beam of light of wavelength 600 nm is incident normally on a slit of width 0.2 mm. If the resulting diffraction pattern is observed on a screen 1 m away, find the distance of (i) first minimum, and (ii) second maximum, from the central maximum.$
OR
Q.4 (b)3 marks $\mu_1$
Q.53 marks $\alpha$
Q.63 marks $Using Huygen's principle, for a plane wavefront incident on a plane reflecting surface, draw the reflected wavefront. Hence prove laws of reflection.$
Q.73 marks $The de-Broglie wavelength associated with an electron is 0.30 nm. Calculate : (a) the speed, and (b) the kinetic energy (in eV), of the electron.$
Q.83 marks ${}^{2}_{1}\mathrm{H} + {}^{3}_{1}\mathrm{H} \longrightarrow {}^{4}_{2}\mathrm{He} + \mathrm{n}$
Q.9 (a)3 marks $1.0 \times 10^{11}$
OR
Q.9 (b)3 marks $\angle\delta = \angle i + \angle e - \angle A$
Q.103 marks $State the working principle of an LED. Write any two important advantages and two disadvantages of LED.$
Q.113 marks $\sqrt{3}$

Section C

1 mark each

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 ( $S_1$ and $S_2$ ) 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 finges depends on the distance between $S_1$ and $S_2$ , the distance of the screen from the plane of $S_1S_2$ and the wavelength of light used.
Q.12 (I)1 mark $y_1 = a \sin \omega t$
Tap an option to check your answer.
Q.12 (II)1 mark $I_0$
Tap an option to check your answer.
Q.12 (III)1 mark $\omega_1$
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Q.12 (IV)1 mark $S_1$
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Q.12 (V)1 mark $Consider the effect on the angular separation of the fringes in a Young's double slit experiment due to the following operations : (i) the screen is moved away from the plane of the slits, (ii) the separation between the two slits is increased till fringes are observed. Which of the following options is correct ?$
Tap an option to check your answer.