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PHYSICS – Code No. 042 SAMPLE QUESTION PAPER CLASS – XII (2025 – 26) Time Allowed: 3 hours Maximum Marks: 70
General Instructions
(1) There are 33 questions in all. All questions are compulsory. (2) This question paper has five sections: Section A, Section B, Section C, Section D and Section E. (3) All the sections are compulsory. (4) Section A contains sixteen questions, twelve MCQ and four assertion reasoning based of 1 mark each , Section B contains five questions of two marks each , Section C contains seven questions of three marks each, Section D contains two case study-based questions of four marks each and Section E contains three long answer questions of five marks each. (5) There is no overall choice. However, an internal choice has been provided in two question in Section B, one question in Section C and all three questions in Section E. You have to attempt only one of the choices in such questions. (6) Use of calculators is not allowed. (7) You may use the following values of physical constants where ever necessary
i. c = 3 x 10^8 m/s ii. me = 9.1 x10-31^ kg iii. mp = 1.7 x10-27^ kg
iv. e = 1.6 x 10-19^ C v. μ 0 = 4π x 10-7^ T m 𝑨−𝟏 vi. h = 6.63 x10-34^ J s vii. ε 0 = 8.854 x10-12^ 𝑪𝟐𝑵−𝟏𝒎−𝟐 viii. Avogadro’s number = 6.023 X 𝟏𝟎𝟐𝟑^ per gram mole
SECTION A Q.No. (^) Question Marks
- If a charged hollow sphere and a solid sphere of aluminum and copper of equal radii are in electrostatic equilibrium, then which of the following statements is true?
(A) Both the spheres are having equal charges. (B) The hollow sphere will have more charge than solid sphere at its surface. (C) The aluminum sphere will have more charge on its surface than copper sphere. (D) If hollow sphere is also made up of aluminum then it will have more charge.
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- A coil contains N turns of insulated copper wire of diameter d and resistivity ρ wound on a cylinder of diameter D. What is the total resistance between the two ends of the coil of copper wire?(given: D>>d)
(A) 4 𝜌𝑁𝐷 𝑑 2 (B) 8 𝜌𝑁𝐷 𝑑 2
(C) 2 𝜌𝑁𝐷 𝑑 2 (D) 12 𝜌𝑁𝐷 𝑑 2
- If the phasor diagram for a device connected to AC supply is as shown in the fig, then which of the following statements is true?
(A) When the frequency of the AC source is increased than the impedance of the device decreases. (B) This device behaves as conducting wire when connected across DC source. (C) When the frequency of the AC source is decreased than the impedance of the device decreases. (D) D. This device stores energy in the form of magnetic potential energy.
- Which of the following statement is true for the radio waves and the gamma rays? (A) The energy of gamma rays is lesser than that of the radio waves. (B) The frequency of the radio waves is higher than that of gamma rays. (C) The radio waves and the gamma rays have the same energy. (D) The energy of radio waves is lesser than that of the gamma rays.
- A glass prism has internal angles of 45°, 45° and 90°. The glass has a critical angle of 45°. Which of the following ray diagrams depicts the possible path the of light through the prism?
(A) (B)
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(C) (D)
For VI-Candidates
The phenomenon of superposition of two waves, resulting in redistribution of energy is known as……………
(A) diffraction (B) interference (C) reflection (D) refraction
- Which of the following transitions corresponds to the emission of the radiation of the maximum wavelength?
(A) I (B) III (C) IV (D) VI
(for V.I. Candidates)
Which of the following transitions corresponds to the emission of the radiation of the maximum wavelength?
I From 4 th^ orbit to 2 nd^ orbit. II From 2 nd^ orbit to 1 st^ orbit. III From 3 rd^ orbit to 4 th^ orbit. IV From 3 rd^ orbit to 2 nd^ orbit. V From 1 st^ orbit to 3 rd^ orbit. VI From 2 nd^ orbit to 3 rd^ orbit.
(A) I (B) III (C) IV (D) VI
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- A charged particle is projected along the axis of a current carrying loop. Which of the following statements is true?
(A) The acceleration of the charged particle will depend on the velocity with which it is projected. (B) The acceleration of the charged particle will depend on the magnitude of the current passing through the coil. (C) The acceleration of the charged particle will depend on the radius of the coil. (D) The charged particle will move with constant velocity.
- Two small identical magnets are allowed to fall freely one through a vertical solenoid of 20 m made up of copper and another in air through the same vertical distance. The time taken by the two magnets to fall will be
(A) same in both the cases. (B) more for the magnet falling in air. (C) more for the magnet falling through the solenoid. (D) infinite.
- The emf generated by an AC generator is given by V=Vo sin ωt, where ω is angular frequency of armature of generator. What will be the emf if the angular frequency is doubled
(A) V=Vo sin 2ωt ( B) V=2Vo sin ωt
(C) V=2Vo sin 2ωt (D) V=Vo sin ωt
- The ratio of the nuclear densities of two nuclei having the mass numbers 8 and 27 is (A) 8:27 (B) 3:2 (C)2:3 (D) 1:
- When we move magnetic compass from point P to Q then which of the following statement is true
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Find,
(I) the emf of the cell and (II) the internal resistance of the cell.
For VI candidates
Find the relation between internal resistance, emf, external resistance and the total current in the circuit?
- A charge q is placed inside a sphere of radius ‘a’ filled with water and another charge 2q is placed inside cube of side ‘2a’ which is vacuumed inside. Find the ratio of the flux linked with the sphere to that linked with the cube. (Take relative permittivity of water as 80)
20(I) Write an expression for the magnetic force per unit length between two parallel thin current carrying wires. Hence define one ampere. OR
20(II) Draw a diagram representing the behaviour of magnetic field lines for a
(A) diamagnetic & (B) paramagnetic substance.
For VI-Candidates
Sate Gauss’s law of magnetism? Hence find the magnetic flux linked with the sphere enclosing a current carrying solenoid?
21(I) How does the impact parameter affect the trajectory of a α – particles scattered by a heavy nucleus? What is the value of impact parameter for head on collision of α
- particles with the nucleus? OR
21(II) (^) Plot a graph showing variation of de-Broglie wavelength λ versus 1 √𝑉^ ,^ where V is accelerating potential for a particle of mass m and charge q. Obtain the slope of this graph.
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SECTION C
- With the help of circuit diagram explain working of the full wave rectifier. 3
- (I) The current I 1 in a wire is getting divided in two wires with currents I 2 and I 3 at a junction in a circuit.The currents in the three wires are related by I 1 = I 2 + I 3.
(A) State the fundamental law from which this relation is derived. (B) Explain the validation of law of conservation of energy in Kirchhoff's voltage law? (II) How the balancing condition gets affected if you are interchanging the galvanometer and the cell in the Wheat stone bridge?
- A fast-moving neutron collides with the nucleus of Plutonium (Pu), thereby producing Xenon (Xe) and Zirconium (Zr) along with neutrons.
(I) Write the nuclear fission reaction. (II) Find the energy released in the above nuclear reaction.
Given atomic masses: m ( 23994 𝑃𝑢^ ) = 239. 052157 u, m ( 10340 𝑍𝑟^ ) = 102. 926597 u, m ( 13454 𝑋𝑒^ ) = 133. 905040 u & m ( 01 𝑛^ ) = 1. 00866 u.
- A compound microscope consists of an objective lens of focal length 0.82 cm and an eyepiece lens of focal length 2.9 cm. An object is placed 0.91 cm from the objective lens. The image is formed at the near point (25 cm) from the eye. (I) Calculate that the angular magnification of the microscope. (II) Draw the ray diagram of compound microscope in normal adjustment.
- Draw the reflected wave front for a plane wave front incident on a plane reflecting surface. Hence verify the laws of reflection using Huygen’s principle.
For VI Candidates
(I) Define wave front? (II) Define wavelet? (III) What will be the shape of the wave front intercepted by a large reflecting type telescope on earth, due to a star far-away from our solar system?
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(I) Ge and Si diodes start conducting at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the value of V 0 changes by (assume that the Ge diode has large breakdown voltage)
(A) 0.2 V (B) 0.4 V
(C) 0.6 V (D) 0.8 V
(II.) The value of V 0 and Id for the network are :
(A) 13 V, 2.32mA (B) 11.7 V, 2.08mA (C) 11.3V, 2.01mA (D) 11V, 1.96mA
(III.) The circuit shown below contains two ideal diodes, each with a forward resistance of 50 Ω. If the battery voltage is 6 V, the current through the 100 Ω resistance (in amperes) is
(A) 0.036 (B) 0.
(C) 0.030 (D) 0.
(IV) In the figure, potential difference between A and B is
(A) Zero (B) 5 V (C) 10 V (D) 15 V
V 0 5.6K
Si Ge 12V
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- Photoelectric effect is phenomenon of the ejection of electrons when the radiation of suitable frequency is made to fall on the surface of a metal. When light of suitable wavelength falls on the emitter C given in the diagram, the photoelectrons are emitted. These photoelectrons are drawn to the collector A. The photoelectric current of the order of a few microamperes can be normally obtained from the device given in figure. The device given converts a change in intensity of illumination into a change in photocurrent. This current can be used to operate control systems and in light measuring devices. The devices are made up of metals with low ionization enthalpies, for example platinum whose work function is 6.35 eV.
(I) If infrared radiation of 3 x 10^11 Hz is used as incident radiation, determine the reading of microammeter? Justify mathematically.
(II) In the given diagram, if terminal B is shifted towards the left then how will it affect the reading of the microammeter? (for V.I. candidates) (II) If the supplied voltage is decreased, then what will be effect on the reading of the microammeter?
(III) Plot a graph showing this variation in reading of micrometre on shifting the terminal B towards the right.
(for V.I. candidates) (III) If the intensity of incident radiation is doubled, by what factor will the kinetic energy change?
SECTION E
31(I) (A) A dielectric slab of thickness t, is introduced between the plates of parallel plate capacitor of area A and separation d (where t<d). Find an expression for the capacitance with the dielectric slab. (B) A copper sphere of capacitor C is dropped in ocean. Will the capacitance of the sphere increase, decrease or remain same? Justify. (C) A capacitor is connected across a source of potential difference V and then the separation ‘d’ between the plates is increased using insulating stick. Plot ‘V’ vs ‘d’ graph for the given capacitor.
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33(I) (A) State the working principle of a moving coil galvanometer? What modification is required in the galvanometer to make its scale linear? (B) If a galvanometer of resistance 49.5Ω has range of 0.05A. What will be the value of resistance needed to convert it in ammeter of range 5A? (C) How these two resistors should be connected to galvanometer in both cases? OR
33(II) (^) (A) An input potential Vin=200 Sin 100 𝜋𝑡 V is provided to an ideal transformer having 1000 turns in primary coil and 100 turns in secondary coil as shown in figure. The load circuit has a resistance of 4Ω, a capacitive reactance of 2Ω and an inductive reactance of 6Ω.
Find:
(i) the output voltage across the load circuit (ii) the current flowing through the load circuit (iii) the power supplied to the load circuit by the transformer
(B) State the working principle of a transformer and explain how it is a key component in the transfer of electrical power over long distances.
