RBSE Class 12 Physics Model Paper 3 English Medium

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RBSE Class 12 Physics Model Paper 3 English Medium are part of RBSE Class 12 Physics Board Model Papers. Here we have given RBSE Class 12 Physics Sample Paper 3 English Medium.

Board RBSE
Textbook SIERT, Rajasthan
Class Class 12
Subject Physics
Paper Set Model Paper 3
Category RBSE Model Papers

RBSE Class 12 Physics Sample Paper 3 English Medium

Time : 3 ¼ hours
Total: 56

General Instructions to the Examinees

  1. Candidate must first his/her Roll No. on the question paper compulsorily.
  2. All the questions are compulsory.
  3. Write the answer to each question in the given answer-book only.
  4. For questions having more than one part, the answer to those parts are to be written together in continuity.
  5. If there is any error/difference/contradiction in Hindi & English version of the question
    paper, the question of Hindi version should be treated valid.
  6. Question Nos Marks per Questions
    1-13 1
    14-24 2
    25-27 3
    28-30 4
  7. There are internal choices in Q. NOs. 21 and 27 to 30.
  8. Use of calculator is not allowed in the examination.

Section – A

Question 1.
What will happen to the capacitance of a parallel plate capacitor if the common area of two plates is doubled? [1]

Question 2.
A carbon resistor of 47kΩ is to be marked with rings of different colours for its identification. Write the sequence of the colours. [1]

Question 3.
A charged particle of charge q moving with velocity v enters along axis of a current carry… ing solenoid. What force is acting on the particle? [1]

RBSE Class 12 Physics Model Paper 3 English Medium

Question 4.
A conductor of length 1m carrying a current of 1A is placed perpendicular to a magnetic field of Igauss. What force is acting on the conductor? [1]

Question 5.
Which direction would a compass needle point if placed right on the magnetic north or south pole? [1]

Question 6.
What are the factors on which self inductance of a coil depends? [1]

Question 7.
Define critical angle. [1]

Question 8.
Name the experiment which established the wave nature of particles. [1]

Question 9.
What is the de-Broglie wavelength of electron accelerated through a potential difference of 100V? [1]

Question 10.
What is SI unit of activity of a radioactive nuclei? Define it. [1]

Question 11.
In a transistor, doping level in base is increased slightly. How will it effect :  [1]

  1. collector current and
  2. base current?

RBSE Class 12 Physics Model Paper 3 English Medium

Question 12.
What is the importance of modulation index? [1]

Question 13.
What do you mean by skip distance and skip zone? [1]

Section – B

Question 14.
Find the total energy stored in the capacitors of the given network. [2]
RBSE Class 12 Physics Model Paper 3 English Medium 1

Question 15.
Explain limitations of Ohm’s law with examples and current-voltage graphs. [2]

Question 16.
Find the equivalent resistance between A and B of the circuit shown in the figure. [2]
RBSE Class 12 Physics Model Paper 3 English Medium 2

Question 17.
A Rowland ring of mean radius 12 cm has 3600 turns of wire wound on a ferromagnetic core of relative permittivity 600. What is the magnetic field in the core for magnetic current 1A? [2]

Question 18.
An AC source of frequency 50Hz is connected to a 50 mH inductor and a bulb. The bulb glows with some brightness. Calculate the capacitance of the capacitor to be connected in series with the bulb so the bulb glows with maximum brightness. [2]

RBSE Class 12 Physics Model Paper 3 English Medium

Question 19.
State Malus law. Draw a graph showing dependance of intensity of transmitted light on the angle between polariser and analyser. [2]

Question 20.
An astronomical telescope uses two lenses of powers 10D and 1D. What is the magnifying
power in normal adjustment and separation between the lenses? [2]

Question 21.
Light of wavelength 2000 Å falls on a metal surface of work function 4.2eV. What is the kinetic energy (in eV) of [2]

  1. the fastest and
  2. the slowest photoelectrons emitted from the surface?

Question 22.
(a) Show that the shortest wavelength lines in Lyman, Balmer and Paschen series have their wavelengths in the ration of 1:4:9.
(b) Show graphically the variation of the radius of the orbit with principal quantum number. [2]
OR
(a) Write any one equation representing nuclear fusion reaction.
(b) A global nuclear war will result in a nuclear winter. What would cause nuclear winter?

Question 23.
If the output of a 2-input NAND gate is fed as input of a NOT gate  [2]

  1. name the new logicgate obtained and
  2. write down its truth table.

Question 24.
What is an electromagnetic wave? Express mathematically a plane electromagnetic wave propagating along x-axis. [2]

RBSE Class 12 Physics Model Paper 3 English Medium

Section – C

Question 25.
Define mean life and half life of a radioactive substance and derive expressions for them. [3]

Question 26.
What is a NOR gate? How is it realised in practice? Give the Boolean expression, ligic symbol and truth table for a NOR gate. [3]

Question 27.
State Ampere’s circuital law. Apply it to find magnetic field near an infinitely long straight conductor carrying current. [3]
OR
How will you convert a galvanometer into an ammeter? How can you increase the range of an ammeter?

Section – D

Question 28.
(a) If an electric dipole is inside a hollow sphere then what is the flux through the surface of the sphere. [4]
(b) Using Gauss’ law derive an expression for electric field due to a uniformly charged thin spherical shell at an outside point.
(c) What is the flux through the surface of a hollow sphere of radius R which encloses a charge Q and how would the flux through the surface change if a medium of dielectric constant k is introduced inside the sphere in place of air.
OR
(a) Define electric potential.
(b) Calculate electric potential V due to a point charge Q at a distance r from it. Draw then graph showing variation of potential with distance due to a point charge.
(c) Calculate the potential on the surface of hydrogen atom of radius 0.5Å.

Question 29.
What do you mean by sharpness of resonance in series LCR circuit. Find an expression for Q factor of the circuit. In which part of series LCR circuit power dissipation occurs? [4]
OR 
(a) Describe the construction and working of a transformer. Obtain an expression for its efficiency.
(b) Explain what is the hysteresis loss in a transformer.
(c) Why long distance transmission of electric power is not possible without transformer?

RBSE Class 12 Physics Model Paper 3 English Medium

Question 30.
(a) Derive an expression for the refractive index of the material of the prism in terms of the angle of the prism and angle of minimum deviation. [4]
b) Draw a graph showing variation of angle of deviation with angle of incidence.
(c) A ray of light passes the through an equilateral prism (n=1.5) such that the angle of incidence is equal to angle of emergence which is equal to 3/4th of angle of prism. Calculate angle of deviation.
OR
(a) Define limit of resolution and resolving power of an optical instrument. How are they related?
(b) Find expressions for resolving power of a telescope and a microscope.
(c) Assume light of wavelength 6000Å is coming from a star. What is the limit of resolution of a telescope whose objective has diameter of 100 inch.

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