CBSE Class 12 Physics Sample Paper 2021 Set B Solved

Read and download PDF of CBSE Class 12 Physics Sample Paper 2021 Set B Solved designed as per the latest curriculum and examination pattern for Class 12 issued by CBSE, NCERT and KVS. The latest Class 12 Physics Sample Papers have been provided with solutions so that the students can solve these practice papers and then compare their answers. This will help them to identify mistakes and improvement areas in Physics Class 12 which they need to study more to get better marks in Class 12 exams. After solving these guess papers also refer to solved Class 12 Physics Question Papers available on our website to build strong understanding of the subject

Sample Paper for Class 12 Physics Pdf

Students can refer to the below Class 12 Physics Sample Paper designed to help students understand the pattern of questions that will be asked in Class 12 exams. Please download CBSE Class 12 Physics Sample Paper 2021 Set B Solved

Physics Class 12 Sample Paper

SECTION A
 
1 Define dielectric constant of a medium. Write its SI unit. 
 
2 Define temperature coefficient of resistivity. 
 
3 A biconcave lens made of a transparent material of refractive index 1.25 is immersed in water of refractive index 1·33. Will the lens behave as a converging or a diverging lens? Give reason.
OR
How does the angle of minimum deviation of a glass prism vary, if the incident violet light is replaced by red light? Give reason.
 
4 Using the concept of force between two infinitely long parallel current carrying conductors, define one ampere of current.
 
5 What is the function of a band pass filter used in a modulator for obtaining AM signal?
OR
What are Universal Logic Gates? Why are they called so?
 
SECTION B
 
6 State Lenz’s law. “The Lenz’s law is a consequence of the principle of conservation of energy.” Justify this statement.
OR
Why is the use of a.c. voltage preferred over d.c. voltage? Give two reasons.
 
7 What are eddy currents? Write their two applications. 
 
8 Explain the term 'drift velocity' of electrons in a conductor. Hence obtain the expression for the current through a conductor in terms of 'drift velocity'.
OR
Describe briefly, with the help of a circuit diagram, how a potentiometer is used to determine the internal resistance of a cell.
 
9 A carrier wave of peak voltage 15 V is used to transmit a message signal. Find the peak voltage of the modulating signal in order to have a modulation index of 60%.
 
10 A ray passes through an equilateral prism such that the angle of incidence is equal to the angle of emergence and the latter is equal to 3/4 of the angle of prism. Find the angle of deviation.
 
11 (i) State law of radioactive decay.
(ii) Plot a graph showing the number (N) of undecayed nuclei as a function of time (t) for a given radioactive sample having half life 1/ 2 T .
 
12 Derive an expression for the de-Broglie wavelength associated with an electron accelerated through a potential V.
 
SECTION C
 
13 Answer the following :
(a) Why are the connections between the resistors in a meter bridge made of thick copper strips?
(b) Why is it generally preferred to obtain the balance point in the middle of the meter bridge wire?
(c) Which material is used for the meter bridge wire and why?
 
14 A parallel plate capacitor is charged by a battery. After sometime the battery is disconnected and a dielectric slab inserted between the plates. How will (i) the capacitance of the capacitor, (ii) potential difference between the plates and (iii) the energy stored in the capacitor be affected?Justify your answer in each case.
 
15 (i) Why do magnetic lines of force form continuous closed loops?
(ii) A small magnet is pivoted to move freely in the magnetic meridian. At what place on the Earth will the magnet be vertical?
(iii) Define the terms magnetic inclination and horizontal component of Earth’s magnetic field at a place.
OR
Using Biot-Savart law derive an expression for the magnetic field due to a circular coil carrying current at a point along its axis.
 
16 (i) Write two characteristic features to distinguish between p-type and n- type semiconductors.
(ii) The current in the forward bias is known to be more (mA) than the current in the reverse bias (μA). What is the reason then to operate the photodiodes in reverse bias?
(iii) Mention any two advantages of LED’s over conventional incandescent lamps.
 
17 Name the following constituent radiations of electromagnetic spectrum which i) produce intense heating effect ii) is absorbed by ozone layer in the atmosphere.iii) used to study crystal structure. Write one application of each of them.
 
18 Give reasons for the following:
(i) For ground wave transmission, size of antenna should be comparable to the wavelength of the signal, e.g. λ/4
(ii) Audio signals converted into electromagnetic waves and they are not transmitted as such directly.
(iii) The amplitude of modulating signal is kept less than that of the carrier wave.
OR
(i) Optical and radio telescopes are built on the ground but X-ray astronomy is possible only from satellites orbiting the Earth. Why?
(ii)Why short wave band is used for long distance radio broad cast?
(iii) Is it necessary for a transmitting antenna to be at the same height as that of the receiving antenna for line-of-sight communication?
 
19 The figure adjoining shows the V-I characteristics of a semiconductor diode.
(i) Identify the semiconductor diode used.
(ii) Draw the circuit diagram to obtain the given characteristic of this device.

CBSE Class 12 Physics Sample Paper 2021 Set B Solved 1

(iii) Briefly explain how this diode can be used as a voltage regulator.
 
20 What is the effect on the interference fringes in a Young’s double slit experiment due to each of the following operations:
(i) The screen is moved away from the plane of the slits
(ii) The source slit is moved closer to the double-slit plane
(iii) The monochromatic source is replaced by a source of white light.
 
21 (i) Name the phenomenon on which the working of an optical fibre is based.
(ii) What are necessary conditions for this phenomenon to occur?
(iii) Draw a diagram to show the behaviour of plane wavefronts as they pass through a thin convex lens.
OR
(i) Draw a labeled diagram of reflecting type telescope.
(ii) Write any two advantages of reflecting type telescope over refracting type.
 
22 (i) Draw a plot of potential energy of pair of nucleons as function of their separations.
(ii) Mark the regions where the nuclear force is (a) attractive and (b) repulsive.
(iii) Write any two characteristic features of nuclear forces.
 
23 (i) How does the stopping potential of a Photo cell change, when
a) the intensity of the incident radiation is halved?
b) frequency of incident radiation increases ?
(ii) Two beams, one of red light and the other of blue light, of the same intensity are incident on a metallic surface to emit photoelectrons. Which one of the two beams emit electrons of greater kinetic energy?
 
24 With the help of a labelled diagram, state the underlying principle of a cyclotron. Explain clearly how it works to accelerate the charged particles.
OR
Draw a labeled diagram of a moving coil galvanometer. Describe briefly its principle and working.


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CBSE Class 12 Physics Sample Paper 2021 Set B Solved

We hope you liked the above provided CBSE Class 12 Physics Sample Paper 2021 Set B Solved. To get an understanding of the type of questions which were asked in exams, it is important for Class 12 students to understand the way sample Paper are set by teachers. Students can download the Sample Paper for Class 12 Physics which will be coming in the exams so that you can practise them and solve all types of questions that can be asked in exams. By doing CBSE Class 12 Physics Sample Paper 2021 Set B Solved you will understand the regular questions and MCQ questions for Class 12 Physics which are always asked. You can download CBSE Class 12 Physics Sample Paper and Class 12 Physics Question Papers in PDF. You should attempt all the last year question paper for Class 12 and Class 12 Physics MCQ Test in examination conditions at home and then compare their answers with the solutions provided by our teachers.

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