CBSE Class 12 Physics 2022 question paper (55/2)

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 $Explain the formation of depletion region in a p-n junction.$
Q.2 (a)2 marks $\alpha$
OR
Q.2 (b)2 marks $v_1$
Q.32 marks $How is an emf generated by a solar cell due to the three basic processes involved ? Explain.$

Section B

3 marks each

Q.4 (a)3 marks $(i) Depict a plane electromagnetic wave propagating along the x-axis. Write the expressions for its oscillating electric and magnetic fields. (ii) Write three characteristics of electromagnetic waves.$
OR
Q.4 (b)3 marks $Name the electromagnetic waves which are produced by the following : (i) Radioactive decays of nucleus (ii) Welding arcs (iii) Hot bodies Write one use each of these waves.$
Q.53 marks $(a) State the conditions for total internal reflection to take place. (b) A tank is filled with a transparent liquid to height 'H'. A coin suspended by a thread in the liquid is gradually lowered till it touches the bottom. The apparent depth is determined corresponding to different positions of the coin. (i) Plot a graph showing variation of the apparent depth with the real depth of the coin. (ii) What is the physical significance of the slope of the graph ?$
Q.6 (a)3 marks $Draw a labelled ray diagram showing the formation of an image by an astronomical refracting telescope in normal adjustment. Hence, obtain the expression for its magnifying power.$
OR
Q.6 (b)3 marks $\lambda$
Q.73 marks $\mu = 1{\cdot}5$
Q.83 marks $-\,3{\cdot}4$
Q.93 marks ${}^{56}_{26}\mathrm{Fe}$
Q.103 marks $Find the ratio of the de Broglie wavelengths associated with an alpha particle and a proton, if both (a) have the same speeds, (b) have the same kinetic energy, (c) are accelerated through the same potential difference.$
Q.113 marks $With the help of a circuit diagram, explain the working of a p-n junction diode as a full-wave rectifier. Also draw its input and output waveforms.$

Section C

1 mark each

The British physicist Thomas Young explained the interference of light using the principle of superposition of waves. He observed the interference pattern on the screen, in his experimental set-up, known now as Young's double slit experiment. The two slits $\mathrm{S_1}$ and $\mathrm{S_2}$ were illuminated by light from a slit S. The interference pattern consists of dark and bright bands of light. Such bands are called fringes. The distance between two consecutive bright and dark fringes is called fringe width.
Q.12 (a)1 mark $\mathrm{S_1}$
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Q.12 (b)1 mark $\mathrm{S_1}$
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Q.12 (c)1 mark $Two sources of light are said to be coherent, when both emit light waves of :$
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Q.12 (d)1 mark $\beta$
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Q.12 (e)1 mark $\mathrm{P_1}$
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Section A

2 marks each

Q.1 (a)2 marks $\alpha$
OR
Q.1 (b)2 marks $v_1$
Q.22 marks $Briefly explain the working of a light emitting diode. Mention its two uses.$
Q.32 marks $Explain the formation of depletion region in a p-n junction.$

Section B

3 marks each

Q.43 marks $With the help of a circuit diagram, explain the working of a p-n junction diode as a full-wave rectifier. Also draw its input and output waveforms.$
Q.53 marks $Find the ratio of the de Broglie wavelengths associated with an alpha particle and a proton, if both (a) have the same speeds, (b) have the same kinetic energy, (c) are accelerated through the same potential difference.$
Q.63 marks ${}^{56}_{26}\mathrm{Fe}$
Q.7 (a)3 marks $(i) Depict a plane electromagnetic wave propagating along the x-axis. Write the expressions for its oscillating electric and magnetic fields. (ii) Write three characteristics of electromagnetic waves.$
OR
Q.7 (b)3 marks $Name the electromagnetic waves which are produced by the following : (i) Radioactive decays of nucleus (ii) Welding arcs (iii) Hot bodies Write one use each of these waves.$
Q.8 (a)3 marks $Draw a labelled ray diagram showing the formation of an image by an astronomical refracting telescope in normal adjustment. Hence, obtain the expression for its magnifying power.$
OR
Q.8 (b)3 marks $\lambda$
Q.93 marks $\lambda_1$
Q.103 marks $\dfrac{4}{3}$
Q.113 marks $\sqrt{2}$

Section C

1 mark each

The British physicist Thomas Young explained the interference of light using the principle of superposition of waves. He observed the interference pattern on the screen, in his experimental set-up, known now as Young's double slit experiment. The two slits $\mathrm{S_1}$ and $\mathrm{S_2}$ were illuminated by light from a slit S. The interference pattern consists of dark and bright bands of light. Such bands are called fringes. The distance between two consecutive bright and dark fringes is called fringe width.
Q.12 (a)1 mark $\mathrm{S_1}$
Tap an option to check your answer.
Q.12 (b)1 mark $\mathrm{S_1}$
Tap an option to check your answer.
Q.12 (c)1 mark $Two sources of light are said to be coherent, when both emit light waves of :$
Tap an option to check your answer.
Q.12 (d)1 mark $\beta$
Tap an option to check your answer.
Q.12 (e)1 mark $\mathrm{P_1}$
Tap an option to check your answer.

Section A

2 marks each

Q.12 marks $The V - I characteristics of a solar cell is shown in the figure. (a) What do the points P and Q represent ? (b) Give the circuit diagram for a solar cell.$
Q.22 marks $Explain the formation of depletion region in a p-n junction.$
Q.3 (a)2 marks $\alpha$
OR
Q.3 (b)2 marks $v_1$

Section B

3 marks each

Q.43 marks ${}^{56}_{26}\mathrm{Fe}$
Q.53 marks $With the help of a circuit diagram, explain the working of a p-n junction diode as a full-wave rectifier. Also draw its input and output waveforms.$
Q.63 marks $An equiconvex lens forms a two times enlarged real image when an object is kept 16 cm from it. The lens is cut into two identical plano-convex lenses. If the object is again kept 16 cm in front of one of these lenses, then find the nature and position of the image formed.$
Q.73 marks $\sqrt{2}$
Q.8 (a)3 marks $(i) Depict a plane electromagnetic wave propagating along the x-axis. Write the expressions for its oscillating electric and magnetic fields. (ii) Write three characteristics of electromagnetic waves.$
OR
Q.8 (b)3 marks $Name the electromagnetic waves which are produced by the following : (i) Radioactive decays of nucleus (ii) Welding arcs (iii) Hot bodies Write one use each of these waves.$
Q.9 (a)3 marks $Draw a labelled ray diagram showing the formation of an image by an astronomical refracting telescope in normal adjustment. Hence, obtain the expression for its magnifying power.$
OR
Q.9 (b)3 marks $\lambda$
Q.103 marks $Find the ratio of the de Broglie wavelengths associated with an alpha particle and a proton, if both (a) have the same speeds, (b) have the same kinetic energy, (c) are accelerated through the same potential difference.$
Q.113 marks $An electron is in the third excited state in a hydrogen atom. It undergoes transitions to the lower energy states. (a) What is the maximum number of spectral lines that can be emitted ? (b) Calculate the minimum wavelength of the spectral lines emitted.$

Section C

1 mark each

The British physicist Thomas Young explained the interference of light using the principle of superposition of waves. He observed the interference pattern on the screen, in his experimental set-up, known now as Young's double slit experiment. The two slits $\mathrm{S_1}$ and $\mathrm{S_2}$ were illuminated by light from a slit S. The interference pattern consists of dark and bright bands of light. Such bands are called fringes. The distance between two consecutive bright and dark fringes is called fringe width.
Q.12 (a)1 mark $\mathrm{S_1}$
Tap an option to check your answer.
Q.12 (b)1 mark $\mathrm{S_1}$
Tap an option to check your answer.
Q.12 (c)1 mark $Two sources of light are said to be coherent, when both emit light waves of :$
Tap an option to check your answer.
Q.12 (d)1 mark $\beta$
Tap an option to check your answer.
Q.12 (e)1 mark $\mathrm{P_1}$
Tap an option to check your answer.