CBSE Term 2 Question Paper for Class 12 Physics

CBSE Term 2 Question Paper for Class 12 – Physics

Question Papers for Physics of Class 12 Exam are important enough for students to practice answer writing style. Physics is one of the most popular subjects in CBSE Examination Board. Every student works a fear towards exams. The Sample Questionnaire appears to be a way to overcome that fear. Class 12 Exam syllabus is much longer. Model Q&A is created based on the complete syllabus. And based on this question and answer, the students get an idea of ​​how they will prepare for the exam. Experts prepare this Question Paper according to the syllabus. Stay involved in the previous year question paper. Seeing the Q&A of it gives the students a special idea on the division of marks. These ideas increase students’ Class 12 in Physics.

CBSE Term 2 Question Paper Class 12 Exam Physics

Board

Central Board of Secondary Education 2022

(CBSE Term 2)

Class

12th

Subject

Physics
Topic

Question Paper

 

Section – A

(a) (i) Define the terms: ‘Impact parameter’ and ‘distance of closet approach’ for an co-operative in Geiger-Marsden scattering experiment.

(ii) What will be the value of the impact parameter for scattering angle (I) θ = 180°?

OR

(b) Photoelectric emission occurs when a surface is irradiated with the radiation of frequency (i) v1, and (II) v2. The maximum kinetic energy of the electrons emitted in the two cases are K and 2K respectively. Obtain the expression for the threshold frequency for the surface.

Briefly explain the working of a light emitting diode. Mention its two uses.

Explain the formation of depletion region in a p-n junction.

 

Section B:

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.

Find the ratio of the de Broglie wavelengths associated with an alpha particle and a proton, if both

(a) Have the same speed

(b) Have the same kinetic energy.

(c) Are accelerated through the same potential difference.

 

(a) Depict the variation of the potential energy of a pair of nucleons with the separation between them.

(b) Imagine the fission of a 56/26 Fe into two equal fragments of 28/13 AI nucleus. Is the fission energetically possible? Justify your answer by working out Q value of the process.

Given: m (56/36 Fe) = 55.93494 u, m (28/13 AI) = 27.98191 u.

 

(7) (a) (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

(b) 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.

 

(8) (a) Draw a labelled ray diagram showing the formation of an image by an astronomical refracting telescope in normal adjustment. Hence, obtain the expression for the magnifying power.

OR

(b) A plane wave front of light of wavelength ‘λ’ is incident normally on a narrow silt of width ‘a’ and a diffraction pattern is observed on screen at a distance ‘D’ from the silt.

(i) Depict the intensity distribution in the pattern observed.

(ii) Obtain the expression for the first maximum from the central maximum.

 

(9) (a) State Bohr’s quantization condition for defining stationary orbits.

(b) Use the energy level diagram shows below to obtain the relation between three wavelengths λ1, λ2 and λ3 emitted due to the transition of electron from the energy states C and B.

 

(10) (a) Is the speed of light in glass independent of the colour of lights? Give reason.

(b) A small bulb is placed at the bottom of a tank containing water in a depth of 70 cm. Find the area of the surface of water though which light from the bulb can emerge out. Given refractive index of water is 4/3.

(11) The refractive index of an equilateral triangular prism kept in air is √2, Calculate:

(a) The angle of minimum deviation

(b) The critical angle for the prism.

 

Section C:

The British physicist Thomas Young explained the interference of light using the principle of superposition of waves. He observed the interference pattern on the experiment. The two alits S1 and S2 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 width.

(a) If the screen is moved closer to the plane of slits S1 and S2, then the fringes width:

(i) Will decrease, but the intensity of bright fringe remains the same.

(ii) Will increase, but the intensity of bright fringe decreases.

(iii) Will decrease, but the intensity of bright fringe increases

(iv) And the intensity both remain the same.

 

(b) What will happen to the pattern on the screen, when the two slits S1 and S2 are replaced by two independent but identical sources?

(i) The intensity of pattern will increase

(ii) The intensity of pattern will decrease

(iii) The number of fringes will become double

(iv) No pattern will be observed as the screen.

 

(c) Two sources of light are said to be coherent, when both emit light waves of

(i) Same amplitude and have a varying phase difference

(ii) Same wavelength and constant phase difference

(iii) Different wavelengths and same intensity

(iv) Different wavelengths and a constant phase differences.

 

(d) The fringe width in a Young’s double slit experiment is β. If the whole set-up immersed in liquid of refractive index ‘μ’, then the new fringe width will be:

(i) β

(ii) βμ

(iii) β/μ

(iv) β/μ2

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