Karnataka 2PUC Preparatory Exam Question Paper 2025 Physics

DISTRICT LEVEL IIPUc PREPARATORY EXAM, JANUARY 2025
Time: 3 Hours Max. Marks: 70
Sub: PHYSICS (33)
General Instructions:
1. All parts 'A' to D' are compulsory. Part- Eis only for visually chllenged students.
2. For Part -A questions first written answer will be considered for awarding marks.
3. Answers without relevant diagram / figure / circuit wherever necessary will not carry any marks.
4. Direct answers tothe numerical problems without relevant fomula and detailed solutions will not carry any maks
PART -A

1. Pick the correct option among the four given optionsfor ALL of the following questions:
15x 1 = 15

1. The property which differentiates two kinds of charge is called the
(A)Polarity of charge (B) Electric charge
(C) Positivity of charge (D) Negativity of charge
(shown in
2. What is the electric field E and charge density o inside a cavity of any conductor?
figure).
(A)E is zero, o is finite other than zero
E=?
(B) E is finite other than zero, o is zero G=?

(C)E is zero, o is infinity
(D) E and o both are zero
per unit electric field.
3. Statement I: Mobility of free electrons in a conductor is the drift velocity
Statement II: The SI Unit of Mobility of free electrons is m/Vs.
(A) Both Statements Iand Il are correct
(B) Statement Iis correct, and Statement Il is wrong
(C) Statement Iis wrong, and Statement Il is correct
(D) Both Statements Iand ll are wrong
4. Lorentz force on a moving electric charge is equalto
(A) difference between electric and magnetic force
(B) the ratio of electric force and magnetic force
(C) sum of both electric and magnetic force
(D) the product of electric force and magnetic force
5. Which of the following is not the property of the magnetic field lines?
Magnetic field lines form closed loops
(A) The
(B) tangent to the field line at a given point represents the direction of the magnetic field
(C)Magnetic field lines intersect each other
(D) Stronger is the magnetic field where there is large number of field lines cross per unit area.
6. "The magnitude of the induced emf in a circuit is equal to the time rate of change of magnetic flux
through the circuit." is:
(A)Gauss's law in electrostatic (B)Gauss's law in magnetism
(C)Ampere's circuital law (D) Faraday's law of electromagnetic induction
7. Polarity of the capacitor in the situation described by figure
(A) Plate - A is positive with respect to B
(B)Plate -A is negative with respect to B
(C) Plate-B is positive with respect to B N
(D) Both Plates AandBare positive
1 P.T.O.

8. In a purely inductive alternative current circuit:
(A)Current leads the voltage by t /2 (B) Current lags the voltage by n/2
(C) Current and voltage are in phase (D) Voltage lags the current by n/2
9. The current due to time rate of change of electric field is:
(A)Conduction current (B) Induced current
(C)Displacement current (D)Current due to flowof charge
(10,Which of the following is the correct eguation of Lens Maker's formula?
1 1 1 (B) f=(ny-)!1
4)-(1-n) R R,) R R,.
1
() f=(1-nai) R R,)
R R
1)Match the following:
Type of sources Type of wave fronts
Point sOurce ata small distance Plane wave front
Point source at a large distance (ii) Cylindrical wave front
c|Linear source at asmall distance (i) Spherical wave front
(A) a -(ii), b-(üi), c- () (B) a- (i), b- (ii), c- (1)
(C)a - (i), b-(i), C- (ii) (D}a- (i), b- (), c- (i)
12.The minimum energy required by an electron to escape from the metal surface is called:
(A) Work function (B) Threshold frequency
(C) Threshold wavelength (D) Stopping potential
13. The value of ionization energy of the hydrogen atom is:
(A) 1.51 eV (B) 3.40 eV (C) 13.6 eV (D) 12.09 eV
14.Which of the following is an example for isobars?
(A) BoH and Au'" (B) H and ,He'
(C) ,H and H (D),C and
(15. ldentify the dopant used in n - type semiconductor.
(A)Arsenic (As) (B) Indium (In) (C) Boron (B) (D) Aluminium (Al)
II. Fillinthe blanks by choosing appropriate answers given in the bracket for ALL the following
questions: 5x1=5
(zero, intensity, mutual induction, self- induction, concentric, interference)
16. Equipotential surfaces of a single point charge are spherical surfaces.
17. The net magnetic flux through any closed surface is
18. Transformer works on the principle of
19. Modification in the distribution of light energy due to the superposition of light is called
20. Photon energy is independent of, of radiation.
2

PART -B
5x2= 10
II. Answer any FVE of the following questions:
21. Mention any two basic properties of charge.
22. State and explain Ohm's law.
carries current 5A. what is the
20. A SOlenoid of length l=Im and has 1000 number of turns. It
l>> radius of the solenoid and
iagnitdde of the magnetic field inside the solenoid? (Here,
Ho=4nX10)
symbols.
24. Wite the expression for induced emf in terms of inductance of a coil and explain the
25. Give any two uses of infrared radiation.
26. What are the two necessal yconditions to happen total internal reflection?
-27. Define power of lens and write its Sl unit.
28. Distinguish between intrinsic and extrinsic semiconductors. (mentioning any two differences.)

PART -C
5x3 =15
IV. Answer any FIVE of the following questions:
29. Derive the expression for torque on a dipole placed in uniform electric field.
30. Obtain the expression for capacitance of a parallel plate capacitor without dielectric medium.
31. Explain, howagalvanometer is converted into avoltmeter?
32. Give any three differences between diamagnetic and ferromagnetic materials.
33. Describe Faraday and Henry's coil-magnet experiment to study electromagnetic induction.
34. Mention any three experimental observations of photoelectric effect.
35. Write three postulates of Bohr's theory of atomic model.

36. Calculate the mass defect of a nitrogen(N") nucleus by using the following data. (Mass of
proton = 1.00783u; Mass of neutron = 1.00867u; Mass of Nitrogen nucleus = 14.00307 u).
PART -D
V. Answer any THREE of the following questions: 3 x 5=15

37. Derive the expression for electric field due to an electric dipole on its axial line.
38. Deduce the balancing condition of a Wheatstone bridge using Kirchhoffs laws.
39. Obtain the expression for magnetic field at any point on the axis of a circular current loop by
applying Biot - Savart's law.
40. (a) Mention any two applications of polaroids. [2M]
(b) Derive the expression for Snell's law of refraction on the basis of Huygen's wave theory
of light. [3M)
41. What is rectification? Explain the working of p - n junction as a ful wave rectifier with circuit
diagram and draw input and output wave forms.

2x 5= 10
VI. Answer any TWOof the following questions:
42. Charges 2uC and 4uC and 6uC are placed at three corners A, Band Crespecively of a square
ABCD of sde x meter. Find what charge must be placed at the fourth corner so that the total
potential at the centre of the square is zero.

43. Calculate the current density and drift velocity of conduction electrons in a copper wire of croSS
sectional area 1.0 x10 m carrying curent of 1.5A. Given free electron density of copper Is
8x1028 electrons/m and e =1.6x10C).

44. A 202 resistor, 1.5H inductor and 35uF capacitor are connected in series with 220V, 50Hz aC
supply. Calculate the impedance of the circuit also find the current through the circuit.

45. Asmall candie, 2.5 cm in size is placed at 27 cm in front of a concave mirror with a radius of
curvature 36 cm. At what distance from the mirror should a screen be placed to obtain a sharp
image? Describe nature and size of the image.

PART -E
(For Visually challenged students only)
7. A bar magnet facing north pole is moved towards the circular conductor, then
(a) Circular conductor face behaves has north pole
(b) Circular conductor face behaves has south pole
(c) In circular conductor current flows in clockwise direction
(d) Bar rnagnet is attracted by the circular conductor

4