# Class 12 Physics Sample Paper Term 1 With Solutions Set B

Please refer to Class 12 Physics Sample Paper Term 1 With Solutions Set B below. These Class 12 Physics Sample Papers will help you to get more understanding of the type of questions expected in the upcoming exams. All sample guess papers for Physics Class 12 have been designed as per the latest examination pattern issued by CBSE. Please practice all Term 1 CBSE Sample Papers for Physics in Standard 12.

## Sample Paper Term 1 Class 12 Physics With Solutions Set B

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. Electric charges under action of electric forces is called
(A) electrostatic
(B) electric flux
(C) electric field
(D) electric field lines

A

Q. 2. Law stating that “force is directly proportional to product of charges and inversely proportional to square of separation between them” is called
(A) Newton’s law.
(B) Coulomb’s law
(C) Gauss’s law.
(D) Ohm’s law

B

Q. 3. In given figure, two positive charges q2 and q3 fixed along the y axis, exert a net electric force in the +x direction on a charge q1 fixed along the x axis. If a positive charge Q is added at (x, 0), the force on q1

(A) shall increase along the positive x-axis.
(B) shall decrease along the positive x-axis.
(C) shall point along the negative x-axis.
(D) shall increase but the direction changes because of the intersection of Q with q2 and q3.

A

Q. 4. The work done to move a charge along an equipotential surface from A to B
(A) cannot be defined.
(B) is a negative quantity.
(C) is zero.
(D) is a positive quantity.

C

Q. 5. The shape of equipotential surfaces due to an isolated charge is
(A) concentric spherical shells and the distance between the shells increases with the decrease in electric field.
(B) concentric spherical shells and the distance between the shells decreases with the decrease in electric field.
(C) equi-spaced concentric spherical shells.
(D) changes with the polarity of the charge.

A

Q. 6. Electric potential inside a conducting sphere
(A) is zero.
(B) remains constant.
(C) decreases from centre to surface.
(D) increases from centre to surface.

B

Q. 7. Kirchhoff’s laws are valid for _______.
(A) only passive circuits.
(B) only linear circuits.
(C) only non-linear circuits.
(D) both (B) and (C).

D

Q. 8. Two resistances are connected in two gaps of Meter Bridge. The balance point is 10 cm from the zero end. A resistance of 20 W is connected in series with the smaller of the two. The null point shifts to 20 cm. What is the value of the bigger resistance?
(A) 89 Ω
(B) 144 Ω
(C) 100 Ω
(D) None of the above

B

Q. 9. A circular current loop of magnetic moment M is in an arbitrary orientation in an external magnetic field B. The work done to rotate the loop by 30° about an axis perpendicular to its plane is
(A) MB
(B) √3MB/2.
(C) MB/2.
(D) zero.

D

Q. 10. When a charge of 1 C moving with velocity 1 m/s normal to a magnetic field experiences a force 1 N, then the magnitude of the magnetic field is
(A) 1 Gauss
(B) 1 Tesla
(C) 1 Orested
(D) None of the above

B

Q. 11. An electron is projected with uniform velocity along the axis of a current carrying long solenoid. Which of the following is true?
(A) The electron will be accelerated along the axis.
(B) The electron path will be circular about the axis.
(C) The electron will experience a force at 45° to the axis and hence execute a helical path.
(D) The electron will continue to move with uniform velocity along the axis of the solenoid.

D

Q. 12. When a charged particle moves through a magnetic field perpendicular to its direction. Then
(A) linear momentum changes.
(B) kinetic energy remains constant.
(C) both (A) and (B)
(D) both linear momentum and kinetic energy varies.

B

Q. 13. A coil of N turns and radius R carries a current I. It is unwound and rewound to make a square coil of side a having same number of turns (N). Keeping the current I same, the ratio of the magnetic moments of the circular coil and the square coil is
(A) π R2/a2
(B) π a2/R2
(C) R2/a2
(D) None of the above

A

Q. 14. A magnetic dipole moment is a vector quantity directed from:
(A) South to North
(B) North to South
(C) East to West
(D) West to East

A

Q. 15. Time period of oscillation of a magnetic needle is
(A) T = √I/MB
(B) T = 2π √I/MB
(C) T = 2π √MB/I
(D) T = π √MB/I

B

Q. 16. A magnetic needle is kept in a non-uniform magnetic field experiences
(A) a force as well as a torque.
(B) a torque but not a force.
(C) a force and a torque.
(D) a force but not a torque.

A

Q. 17. The self-inductance L of a solenoid of length l and area of cross-section A, with a fixed number of turns N increases as
(A) l and A increase.
(B) l decreases and A increases.
(C) l increases and A decreases.
(D) both l and A decrease.

B

Q. 18. An iron-cored solenoid has self inductance 2.8 H. When the core is removed, the self inductance becomes 2 mH. The relative permeability of the material of the core is
(A) 1400
(B) 1200
(C) 2800
(D) 2000

A

Q. 19. To reduce the resonant frequency in an L-C-R series circuit with a generator
(A) the generator frequency should be reduced.
(B) another capacitor should be added in parallel to the first.
(C) the iron core of the inductor should be removed.
(D) dielectric in the capacitor should be removed.

B

Q. 20. L, C and R represent physical quantities inductance, capacitance and resistance. The combination which has the dimensions of frequency is

A

Q. 21. When the distance between the parallel plates of a parallel plate capacitor is halved and the dielectric constant of the dielectric used is made three times, then the capacitance becomes
(A) 3 times
(B) 6 times
(C) 4 times
(D) 2 times

B

Q. 22. In balanced condition of a Wheatstone bridge, there is:
(A) no current flow through the galvanometer
(B) no current flow through the resistors
(C) no current is drawn from the voltage source
(D) current flow through galvanometer becomes maximum.

A

Q. 23. The magnetic field at the ends of a very long current carrying solenoid is
(A) same as that at the centre.
(B) half as that at the centre.
(C) one -fourth as that at the centre.
(D) none of the above

B

Q. 24. The magnetic field produced by a current carrying solenoid is independent of its
(A) length.
(B) area of cross section.
(C) both (A) and (B)
(D) none of the above

C

Q. 25. The basic difference between magnetic lines of force and electric lines of force is
(A) magnetic lines of force are continuous and electric lines of force are discontinuous.
(B) electric lines of force are continuous and magnetic lines of force are discontinuous.
(C) magnetic lines of force intersect each other and electric lines of force do not intersect each other.
(D) electric lines of force intersect each other and magnetic lines of force do not intersect each other.

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. Toroid is a
(A) fixed value resistor.
(B) capacitor.
(C) inductor.
(D) variable resistor.

C

Q. 27. 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

A

Q. 28. A toroid has ________ inductance, for a given number of turns, than a solenoid with a core of same material and similar size.
(A) same
(B) more
(C) less
(D) variable

B

Q. 29. 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.

B

Q. 30. Why inductance of solenoid is more than the inductance of a solenoid having same number of turns, core of same material and similar size?
(A) Core is endless hence there is no leakage of flux.
(B) Resistance of wire is less hence magnitude of current flow is more
(C) Number of turns per unit length is more.
(D) Both (A) and (B)

A

Q. 31. Why sound system engineers prefer to use toroidal transformer?
(A) It is cheaper.
(B) It is lighter.
(C) It is compact.
(D) It does not create vibration or hum.

D

Q. 32. Average magnetic field strength in the Earth’s outer core is:
(A) 5 Gauss
(B) 25 Gauss
(C) 500 Gauss
(D) Cannot be measured

B

Q. 33. Efficiency of toroidal transformer is around ______ % which is ______ than laminated core transformer.
(A) 95, lower
(B) 95, higher
(C) 50, lower
(D) 80, higher

B

Q. 34. Which of the following statements is true ?
(A) Earth’s magnetic field is due to electric current induced in the ionosphere.
(B) The average magnetic field strength in the Earth’s outer core is equal to the magnetic field at the surface.
(C) Earth’s magnetic field reverses at an average interval of approximately 3,00,000 years.
(D) Angle of dip is same at every point of the surface of Earth.

C

Q. 35. According to Faraday’s law of electromagnetic induction :
(A) electric field is produced by time varying magnetic field.
(B) magnetic field is produced by time varying electric field.
(C) Both (A) and (B).
(D) None of these

A

Q. 36. If a coil of insulated wire connected to a battery is brought to galvanometer, its pointer is deflected, because
(A) a current is induced in the galvanometer coil.
(B) the coil produces a magnetic field.
(C) the coil produces an electric field.
(D) None of these

A

Q. 37. The polarity of induced emf is defined by
(B) Biot-Savart law
(C) Lenz’s law
(D) Fleming’s left hand rule

C

Q. 38. The resistors of resistance boxes are made by double folded wire to nullify the effect of :
(A) heating.
(B) magnetism.
(C) self induction.
(D) None of the above

C

Q 39. A magnet is moved towards a coil (i) quickly (ii) slowly.
(A) Induced e.m.f. is more in case (i).
(B) Induced e.m.f. is less in case (i).
(C) Induced e.m.f.s are equal in both the cases.
(D) In which case induced e.m.f. will be more that depends upon the radius of the coil.

A

Q. 40. Two identical coaxial circular coils carry same current in same direction. If the loops approach each other then the current
(A) increases.
(B) decreases.
(C) remains the same.
(D) in one coil current increases and in the other coil decreases.

B

Q. 41. When current in a coil changes from 7 A to 2 A in 0.1 s, 50 V is induced. The self-inductance of the coil is
(A) 1 H
(B) 2 H
(C) 3 H
(D) 4 H

A

Q. 42. A unit positive charge is taken from one point to another over an equipotential surface. Then
(A) no work is done.
(B) work is done on the charge.
(C) work is done by the charge.
(D) work done is constant.

A

Q. 43. A hollow metal sphere is so charged that the potential on its surface is 10 V. The potential at the centre of the sphere is
(A) 10 V
(B) 0 V
(C) Depends on the radius of the sphere
(D) None of the above

A

Q. 44. A current or a (electric or magnetic) field (i) emerging out of the plane of the paper and (ii) going into the plane of the paper is depicted by
(A) Both by a dot
(B) Both by a cross.
(C) (i) By a dot Θ (ii) by a cross ⊗
(D) (i) by a cross ⊗ (ii) by a dot Θ

C

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) : Circuit containing capacitors should be handled very carefully even when the power is off.
Reason (R) : The capacitors may break down at any time.

C

Q. 46. Assertion (A) : Kirchhoff’s voltage law indicates that the electric field is conservative.
Reason (R) : Potential difference between two points in a circuit does not depend on the path.

A

Q. 47. Assertion (A) : In balanced condition, if the galvanometer and the voltage source is interchanged, the balanced condition remains same.
Reason (R) : The balanced condition of Wheatstone bridge does not depend on the value of the resistances.

C

Q. 48. Assertion (A) : When the magnetic flux changes around a metallic conductor, the eddy current is produced.
Reason (R) : Electric potential determines the flow of charge.

B

Q. 49. Assertion (A) : The cores of electromagnets are made of soft iron.
Reason (R) : Coercivity of soft iron is small.

A

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. Magnetic flux is a _____ quantity and its unit is ________ .
(A) Scalar quantity, Weber
(B) Vector quantity, Weber
(C) vector quantity, Tesla Meter square
(D) Scalar quantity, Tesla

A

Q. 51. An induced e.m.f. produced by inserting a magnet into a coil is independent of
(A) the strength of the magnet
(B) number of turns of coil
(C) the resistance of the wire of the coil
(D) speed with which the magnet is inserted

C

CASE STUDY

Read the following text and answer the following questions on the basis of the same :

Power factor corrector capacitor
Power factor correction is a method to reduce the lagging power factor in inductive loads by fixing a high value capacitor across the phase and neutral line close to the load. When the Voltage and Current are in phase with each other in an AC circuit, the energy from the source is fully converted into another form to drive the load and in this case power factor is in unity. When the power factor drops, the system becomes less efficient.
In inductive loads, current “lags” the voltage leading to “lagging power factor”. Power factor correction is the method to reduce the lagging power factor in inductive loads by fixing a high value capacitor across the phase and neutral close to the load. These capacitors have leading power factor so that it will neutralize the lagging power factor of the load.
Power capacitors are huge non polarized metal film electrolytic type capacitors.
Capacitors should be sufficiently rated to the load capacity. It should be connected to the lines, only when the loads are running and drawing current. Only the passage. Nothing else.

Q. 52. What is meant by power factor correction?
(A) The method to reduce the lagging power factor in inductive loads
(B) The method to enhance the lagging power factor in inductive load
(C) The method to reduce the lagging power factor in capacitive loads
(D) The method to enhance the lagging power factor in capacitive loads

A

Q. 53. When the energy from source is fully converted into another form, the power factor is
(A) 0.5
(B) 1.0
(C) 0
(D) ∞

B

Q. 54. Power capacitors for power factor correction are
(A) polarized metal film electrolytic type.
(B) non-polarized metal film electrolytic type.
(C) non-polarized metal film non-electrolytic type.
(D) polarized ceramic non- electrolytic type.