Please refer to Class 12 Physics Sample Paper Term 1 Set C with solutions below. The following CBSE Sample Paper for Class 12 Physics has been prepared as per the latest pattern and examination guidelines issued by CBSE. By practicing the Physics Sample Paper for Class 12 students will be able to improve their understanding of the subject and get more marks.
CBSE Class 12 Physics Sample Paper for Term 1
Section – A
This section consists of 25 multiple choice questions with overall choice to attempt any 20 questions. In case more than desirable number of questions are attempted, ONLY first 20 will be considered for evaluation.
Q. 1. A point positive charge is brought near an isolated conducting sphere in Figure. The electric field is best given by :
(A) Fig (i)
(B) Fig (iii)
(C) Fig (ii)
(D) Fig (iv)
Answer
B
Q. 2. In a potentiometer of 5 wires, the balance point is obtained on the 3rd wire. To shift the balance point to the 4th wire,
(A) current of the main circuit is to be decreased.
(B) current of the main circuit is to be increased.
(C) the shifting is not possible
(D) None of the above
Answer
A
Q. 3. At resonance, the impedance in series LCR circuit is
(A) maximum.
(B) zero.
(C) infinity.
(D) minimum.
Answer
D
Q. 4. In a LCR circuit having L = 8.0 henry, C = 0.5 μF and R = 100 ohm in series. The resonance frequency in per second is :
(A) 600 radian
(B) 600 Hz
(C) 500 radian
(D) 500 Hz
Answer
C
Q. 5. Ratio of total intensity of magnetic field at equator to poles is
(A) 1 : 1
(B) 1 : 2
(C) 2 : 1
(D) None of the above
Answer
A
Q. 6. An infinitely long straight conductor is bent into the shape as shown in the figure. Current in it is i and the radius of the circular loop is r. The magnetic field at its centre is
(A) Zero
(B) Infinite
(C) μ0i/2πr (π – 1)
(D) μ0i/2πr (π + 1)
Answer
C
Q. 7. A point charge +q, is placed at a distance d from an isolated conducting plane. The field at a point P on the other side of the plane is
(A) directed perpendicular to the plane and away from the plane.
(B) directed perpendicular to the plane but towards the plane.
(C) directed radially away from the point charge.
(D) directed radially towards the point charge.
Answer
A
Q. 8. The power factor of series LCR circuit at resonance is
(A) 0.707
(B) 1
(C) 0.5
(D) 0
Answer
B
Q. 9. The strength of the magnetic field at distance r from a long straight current carrying wire is B. The field at a distance r/2 will be
(A) B
(B) 2B
(C) B/2
(D) B/4
Answer
B
Q. 10. A hemisphere is uniformly charged positively. The electric field at a point on a diameter away from the centre is directed
(A) perpendicular to the diameter.
(B) parallel to the diameter.
(C) at an angle tilted towards the diameter.
(D) at an angle tilted away from the diameter.
Answer
A
Q. 11. The deflecting torque acting on the coil of a galvanometer is
(A) inversely proportional to number of turns.
(B) inversely proportional to current flowing.
(C) inversely proportional to area of the coil.
(D) directly proportional to the magnetic field strength.
Answer
D
Q. 12. The electric flux through the surface :
(A) in Figure (iv) is the largest.
(B) in Figure (iii) is the least.
(C) in Figure (ii) is same as Figure (iii) but is smaller than Figure (iv).
(D) is the same for all the figures.
Answer
D
Q. 13. A solenoid of 1.5 metre length and 4.0 cm diameter has 10 turn per cm. A current of 5 A ampere is flowing through it. The magnetic field at axis inside the solenoid is
(A) 2π × 10–3 T
(B) 2π × 10–3 G
(C) 2π × 10–7 T
(D) 2π × 10–7 G
Answer
A
Q. 14. Capacitance of a parallel plate capacitor can be increased by
(A) increasing the distance between the plates.
(B) decreasing the distance between the plates.
(C) decreasing the area of plates.
(D) increasing the thickness of the plates.
Answer
B
Q. 15. In a moving coil galvanometer, current in the coil is
(A) directly proportional to angle of deflection.
(B) inversely proportional to the angle of deflection.
(C) directly proportional to the square root of the angle of deflection.
(D) inversely proportional to the square root of the angle of deflection.
Answer
A
Q. 16. Which error of meter bridge is removed when the known and unknown resistances are interchanged?
(A) End error
(B) Measurement error
(C) Percentage error
(D) Parallax error
Answer
A
Q. 17. In the following circuit, the bulb will become suddenly bright if :
(A) contact is made or broken.
(B) contact is made.
(C) contact is broken.
(D) won’t become bright at all.
Answer
C
Q. 18. Current sensitivity of a galvanometer is given by
(A) Cq/nBA
(B) nBA/C
(C) nBA/CG
(D) CG/nBA
Answer
B
Q. 19. In a pure inductive circuit or in an ac circuit containing inductance only, the current :
(A) leads the e.m.f. by 90°.
(B) lags behind the e.m.f. by 90°.
(C) sometimes leads and sometime lags behind the e.m.f.
(D) is in phase with the e.m.f.
Answer
B
Q. 20. The energy of a charged capacitor is given by the expression (q is the charge on the conductor and C is its capacity) :
(A) q2/2C
(B) q2/C
(C) 2qC
(D) q/2C2
Answer
A
Q. 21. When a capacitor C is charged to a certain potential and connected to an inductor L, then frequency of energy oscillation is given by
(A) 1/2π√LC
(B) 1/√LC
(C) 2π/√LC
(D) 1/2π √L/C
Answer
A
Q. 22. An electron and a proton are in a uniform electric field, the ratio of their accelerations will be :
(A) zero
(B) unity
(C) the ratio of the masses of proton and electron.
(D) the ratio of the masses of electron and proton.
Answer
C
Q. 23. A parallel plate condenser has a capacitance 50 μF in air and 110 μF when immersed in an oil. The dielectric constant ′K′ of the oil is :
(A) 0.45
(B) 0.55
(C) 1.10
(D) 2.20
Answer
D
Q. 24. In an A.C. circuit containing only capacitance, the current :
(A) leads the voltage by 180°
(B) lags the voltage by 90°
(C) leads the voltage by 90°
(D) remains in phase with the voltage
Answer
C
Q. 25. In the circuit shown in Figure, initially key K1 is closed and key K2 is open. Then K1 is opened and K2 is closed. Then
(A) Voltage across C1 = Voltage across C2
(B) Voltage across C1 > Voltage across C2 , if C1 > C2
(C) Charge on C1 = charge on C2
(D) None of the above
Answer
A
Section – B
This section consists of 24 multiple choice questions with overall choice to attempt any 20 questions. In case more than desirable number of questions are attempted, ONLY first 20 will be considered for evaluation.
Q. 26. A capacitor is charged by using a battery which is then disconnected. A dielectric slab is then slipped between the plates, which results in :
(A) Reduction of charge on the plates and increase of potential difference across the plates
(B) Increase in the potential difference across the plate, reduction in stored energy, but no change in the charge on the plates
(C) Decrease in the potential difference across the plates, reduction in the stored energy, but no change in the charge on the plates
(D) None of the above
Answer
C
Q. 27. A voltmeter has resistance of 2000 ohms and it can measure upto 2V. If we want to increase its range to 10 V, then the required resistance in series will be :
(A) 2000 Ω
(B) 4000 Ω
(C) 6000 Ω
(D) 8000 Ω
Answer
D
Q. 28. Magnetic field intensity at the centre of coil of 50 turns, radius 0.5 m and carrying a current of 2 A is :
(A) 0.5 × 10−5 T
(B) 1.25 × 10−4 T
(C) 3 × 10−5 T
(D) 4 × 10−5 T
Answer
B
Q. 29. Under the influence of a uniform magnetic field a charged particle is moving in a circle of radius R with constant speed v. The time period of the motion :
(A) depends on R and not on v
(B) depends on v and not on R
(C) depends on both R and v
(D) is independent of both R and v
Answer
D
Q. 30. Two thin long parallel wires separated by a distance b are carrying a current i amp each. The magnitude of the force per unit length exerted by one wire on the other is :
(A) μ0i2 / b2
(B) μ0i2 / 2πb
(C) μ0i / 2πb
(D) μ0i / 2πb2
Answer
B
Q. 31. A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil of n turns. The magnetic field at the centre of this coil of n turns will be :
(A) nB
(B) n2B
(C) 2nB
(D) 2n2B
Answer
B
Q. 32. A current of 2 A flows in a system of conductors as shown.
The potential difference (VA – VB) will be :
(A) + 2V
(B) + 1V
(C) – 1 V
(D) – 2 V
Answer
B
Q. 33. The potential gradient along the length of a uniform wire is 10 volt/metre. B and C are the two points at 30 cm and 60 cm point on a meter scale fitted along the wire. The potential difference between B and C will be :
(A) 3 volt
(B) 0.4 volt
(C) 7 volt
(D) 4 volt
Answer
A
Q. 34. n equal resistors are first connected in series and then parallel. What is the ratio of the maximum to minimum resistance?
(A) n
(B) 1 / n2
(C) n2
(D) 1/n
Answer
C
Q. 35. A wire of length L and resistance R is stretched to get the radius of cross-section half. What is new resistance :
(A) 5 R
(B) 8 R
(C) 4 R
(D) 16 R
Answer
D
Q. 36. 100 cells each of emf 5V and internal resistance 1 Ω are to be arranged so as to produce maximum current in a 25 Ω resistance. Each row contains equal number of cells. The number of rows should be :
(A) 2
(B) 4
(C) 5
(D) 100
Answer
A
Q. 37. In a meter bridge, the balancing length from the left end (standard resistance of one ohm is in the right gap) is found to be 20 cm. The value of the unknown resistance is :
(A) 0.8 Ω
(B) 0.5 Ω
(C) 0.4 Ω
(D) 0.25 Ω
Answer
D
Q. 38. A potentiometer consists of a wire of length 4 m and resistance 10 Ω. It is connected to a cell of e.m.f. 2 V. The potential difference per unit length of the wire will be :
(A) 0.5 V/m
(B) 2 V/m
(C) 5 V/m
(D) 10 V/m
Answer
A
Q. 39. Three condensers each of capacitance 2 F are put in series. The resultant capacitance is :
(A) 6 F
(B) 3/2 F
(C) 2/3 F
(D) 5 F
Answer
C
Q. 40. When air in a capacitor is replaced by a medium of dielectric constant K, the capacity :
(A) Decreases K times
(B) Increases K times
(C) Increases K2 times
(D) Remains constant
Answer
B
Q. 41. 1000 small water drops each of radius r and charge q coalesce together to form one spherical drop. The potential of the big drop is larger than that of the smaller drop by a factor of
(A) 1000
(B) 100
(C) 10
(D) 1
Answer
B
Q. 42. Two insulated charged spheres of radii 20 cm and 25 cm respectively and having an equal charge Q are connected by a copper wire, then they are separated :
(A) both the spheres will have the same charge Q.
(B) charge on the 20 cm sphere will be greater than that on the 25 cm sphere.
(C) charge on the 25 cm sphere will be greater than that on the 20 cm sphere.
(D) charge on each of the sphere will be 2Q.
Answer
C
Q. 43. The condensers of capacity C1 and C2 are connected in parallel, then the equivalent capacitance is:
(A) C1 + C2
(B) C1C2/C1 + C2
(C) C1 / C2
(D) C2 / C1
Answer
A
Q. 44. Two charged spheres of radii 10 cm and 15 cm are connected by a thin wire. No current will flow, if they have :
(A) The same charge on each
(B) The same potential
(C) The same energy
(D) The same field on their surfaces
Answer
B
Given below are two statements labelled as Assertion (A) and Reason (R)
Directions: In the following questions, a statement of Assertion (A) and is followed by a statement of Reason (R). Mark the correct choice as:
(A) Both Assertion (A) and Reason (R) are true, and Reason(R) is the correct explanation of (A).
(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
(C) Assertion (A) is true, but Reason (R) is false.
(D) Assertion (A) is false, but Reason (R) is true.
Q. 45. Assertion (A): In a cavity in a conductor, the electric field is zero.
Reason (R): Charges in a conductor reside only at its surface.
Answer
A
Q. 46. Assertion (A): Three point charges Q1, Q2 and Q3 are shown in the figure. The flux over the Gaussian surface depends on only one charge point.
Reason (R): Electric flux depends on the all charges nearby.
Answer
D
Q. 47. Assertion (A): Two parallel metal plates having charge +Q and –Q are facing at a distance between them. The plates are now immersed in kerosene oil and the electric potential between the plates decreases.
Reason (R): Dielectric constant of kerosene oil is less than 1.
Answer
C
Q. 48. Assertion (A): Potentiometer is used to measure the e.m.f. of a cell.
Reason (R): Potentiometer is preferred over voltmeter to measure the e.m.f. a cell since it does not draw any net current from the cell.
Answer
A
Q. 49. Assertion (A): Torque on a coil is maximum when it is suspended radially in a magnetic field.
Reason (R): Torque tends to rotate a coil .
Answer
B
Section – C
This section consists of 6 multiple choice questions with an overall choice to attempt any 5. In case more than desirable number of questions are attempted, ONLY first 5 will be considered for evaluation.
Q. 50. When a proton is accelerated through 1 V, then its kinetic energy will be :
(A) 1840 eV
(B) 13.6 eV
(C) 1 eV
(D) 0.54 eV
Answer
C
Q. 51. Electric field strength due to a point charge of 5μC at a distance of 80 cm from the charge is :
(A) 8 × 104 N/C
(B) 7 × 104N/C
(C) 5 × 104 N/C
(D) 4 × 104 N/C
Answer
B
CASE STUDY
Read the following text and answer the following questions on the basis of the same:
Earth’s magnetism: Earth’s magnetic field is caused by a dynamo effect. The effect works in the same way as a dynamo light on a bicycle. Magnets in the dynamo start spinning when the bicycle is pedaled, creating an electric current. The electricity is then used to turn on the light. This process also works in reverse. If you have a rotating electric current, it will create a magnetic field. On Earth, flowing of liquid metal in the outer core of the planet generates electric currents. The rotation of Earth on its axis causes these electric currents to form a magnetic field which extends around the planet. The average magnetic field strength in the Earth’s outer core was measured to be 25 Gauss, 50 times stronger than the magnetic field at the surface. The magnetic field is extremely important for sustaining life on Earth. Without it, we would be exposed to high amounts of radiation from the Sun and our atmosphere would be free to leak into space. This is likely what happened to the atmosphere on Mars. As Mars doesn’t have flowing liquid metal in its core, it doesn’t produce the same dynamo effect. This left the planet with a very weak magnetic field, allowing for its atmosphere to be stripped away by solar winds, leaving it uninhabitable. Based upon the study of lava flows throughout the world, it has been proposed that the Earth’s magnetic field reverses at an average interval of approximately 300,000 years. However, the last such event occurred some 780,000 years ago.
Q. 52. Which of the followings is the reason for Earth’s magnetism ?
(A) Rotation of electric current
(B) Rotation of Earth
(C) Attraction due to other celestial bodies
(D) Solar flares
Answer
A
Q. 53. Electric current in the Earth’s body is generated due to:
(A) movement of charged particle in the atmosphere.
(B) flowing of liquid metal in the outer core.
(C) electric discharges during thunderstorm.
(D) its revolution round the Sun.
Answer
A
Q. 54. Which planet has no own magnetic field ?
(A) Jupiter
(B) Neptune
(C) Mars
(D) Mercury
Answer
C
Q. 55. Average magnetic field strength in the Earth’s outer core is :
(A) 5 Gauss
(B) 25 Gauss
(C) cannot be measured
(D) 50 Gauss
Answer
B
