# Sample Paper Class 12 Physics Term 1 Set C

Please refer to Sample Paper Class 12 Physics Term 1 Set C with solutions provided below. We have provided CBSE Sample Papers for Class 12 Physics as per the latest paper pattern and examination guidelines for Standard 12 Physics issued by CBSE for the current academic year. The below provided Sample Guess paper will help you to practice and understand what type of questions can be expected in the Class 12 Physics exam.

## CBSE Sample Paper Class 12 Physics for Term 1 Set C

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. “Total electric flux out of a closed surface is equal to the charge enclosed divided by the permittivity”.
This is known as
(A) Gauss’s Law
(C) Maxwell’s law
(D) Coulomb’s law

A

Q. 2. In spite of variation of which of the following parameter, the capacitance of a parallel plate capacitor remains unaffected?
(A) Thickness of the plate
(B) Area of the plate
(C) Distance between the plates
(D) Dielectric between the two plates

A

Q. 3. Two parallel plate capacitors C1 and C2 have same dimensions. C1 has dielectric of dielectric constant K1 and C2 has dielectric of dielectric constant K2. If K1 > K2, then which one will store more charge?
(A) C1
(B) C2
(C) Both will have same charge
(D) This will depend on applied voltage.

A

Q. 4. An uncharged body gets charged by keeping it closed to a charged body. This phenomenon is known as
(A) Conduction
(B) Induction
(C) Isolation
(D) Magnetization

B

Q. 5. A transformer having efficiency of 90% is working on 200 V and 3 kW power supply. If the current in the secondary coil is 6 A, the voltage across the secondary coil and the current in the primary coil respectively are
(A) 450 V, 13.5 A
(B) 600 V, 15 A
(C) 300 V, 15 A
(D) 450 V, 15 A

D

Q. 6. In a Wheatstone bridge if the galvanometer and the voltage source are interchanged which of the following observations will be true?
(A) Deflection of galvanometer will be reversed
(B) Deflection of galvanometer will increase.
(C) Deflection of galvanometer will decrease.
(D) Deflection of galvanometer will remain same.

D

Q. 7. If one end of each of the given n number of resistors are joined together and similarly other ends of all the resistors are joined together, then the combination is a
(A) Series combination
(B) Parallel combination
(C) Either (A) or (B)
(D) Combination of (A) and (B)

B

Q. 8. In a potentiometer of 10 wires, the balance point is achieved on 6th wire. To shift the balance point to 9th wire
(A) Resistance to be increased in series with the cell whose e.m.f. is to be measured.
(B) Resistance to be decreased in series with the cell whose e.m.f. is to be measured.
(C) Resistance to be increased in the primary circuit
(D) Resistance to be decreased in the primary circuit

C

Q. 9. In electronic circuits flow of current is shown from positive terminal of a battery to its negative terminal. This current known as
(A) Alternating current
(B) Pulsating current
(C) Eddy current
(D) Conventional current

D

Q. 10. In a equation XY = Z, if Z represents the current density, X represents the electric field then Y represents
(A) Resistivity
(B) Conductivity
(C) Resistance
(D) Potential difference

B

Q. 11. The effective resistance in the following circuit between the points A and B is

(A) 10Ω
(B) 5Ω
(C) 20Ω
(D) 40Ω

C

Q. 12. A short bar magnet has a magnetic moment of 0.5 JT-1. The magnitude and direction of the magnetic field produced by the magnet at a distance 5 cm from the centre of magnet on the axis is
(A) 8 × 10–4 T along SN
(B) 8 × 10–4 T along NS
(C) 4 × 10–4 T along SN
(D) 4 × 10–4 T along NS

A

Q. 13. The torque acting on a current carrying loop is placed in a uniform magnetic field depends upon
(A) area of loop
(B) magnitude of current
(C) magnetic field
(D) all of the above

D

Q. 14. When a strong magnetic field is applied to a stationary electron, the electron
(A) Moves in the direction of the field
(B) Remains stationary
(C) Moves in the opposite direction of the field
(D) spins

B

Q. 15. A charged particle is moving in circular orbit with velocity v in a uniform magnetic field B. If the velocity of charged particle and strength of magnetic field both are doubled, then radius of the circular orbit
(A) increases
(B) Remains same
(C) decreases
(D) depends of the magnitude of the charge

B

Q. 16. Two identical coaxial coils X and Y carrying current of same magnitude in the same direction are brought closer. The current
(A) Both in X and Y will increase
(B) Both in X and Y will decrease
(C) In X will increase and in Y will decrease
(D) In Y will increase and in X will decrease

B

Q. 17. A metal plate may be heated
(A) By sending direct current through it
(B) By sending alternating current through it
(C) By placing it in a time varying magnetic field
(D) By all of the above processes

D

Q. 18. Two inductors L1 and L2 are connected in series. The equivalent inductance is
(A) L1L2/L1 + L2
(B) L1 + L2
(C) L1 + L2 /2
(D) L1L2

B

Q. 19. Which of the following is dimensionally different from the others?
(A) 1/RC
(B) R/L
(C) RC
(D) 1/√LC

C

Q. 20. The dimensional formula of impedance is
(A) [ML2 T–3 A–2]
(B) [ML2 T–2 A–2]
(C) [M–1 L–2 T4 A2]
(D) [ML–3 T–3 A–2 ]

A

Q. 21. A charge Q is enclosed by a Gaussian spherical surface of radius R. If the radius is doubled, then the outward electric flux will :
(A) increase four times
(B) be reduced to half
(C) remain the same
(D) be doubled

C

Q. 22. A charge Q is placed at the centre of the line joining two equal charges Q. The system of the three charges will be in equilibrium, if Q is equal to :
(A) − Q/2
(B) − Q/4
(C) Q/4
(D) Q/2

B

Q. 23. A battery of 6 volts is connected to the terminals of a three metre long wire of uniform thickness and resistance of the order of 100 Ω. The difference of potential between two points separated by 50 cm on the wire will be :
(A) 1 V
(B) 1.5 V
(C) 2 V
(D) 3 V

A

Q. 24. A charged particle moves through a magnetic field in a direction perpendicular to it. Then the
(A) Speed of the particle remains unchanged
(B) Direction of the particle remains unchanged
(C) Acceleration remains unchanged
(D) Velocity remains unchanged

A

Q. 25. Magnetic field due to 0.1 A current flowing through a circular coil of radius 0.1 m and 1000 turns at the centre of the coil is :
(A) 2 × 10−1 T
(B) 4.31 × 10−2 T
(C) 6.28 × 10−4 T
(D) 9.81 × 10−4 T

C

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. Two cities are 150 km apart. Electric power is sent from one city to another city through copper wires. The fall of potential per km is 8 volt and the average resistance per km is 0.5 Ω. The power loss in the wire is:
(A) 19.2 W
(B) 19.2 kW
(C) 19.2 J
(D) 12.2 kW

B

Q. 27. The current I in a coil varies with time as shown in the figure. The variation of induced emf with time would be :

B

Q. 28. A copper ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet while it is passing through the ring is :
(A) Equal to that due to gravity
(B) Less than that due to gravity
(C) More than that due to gravity
(D) Depends on the diameter of the ring and the length of the magnet

B

Q. 29. The average e.m.f. induced in a coil in which a current changes from 0 to 2 A in 0.05 s is 8 V. The self inductance of the coil is :
(A) 0.1 H
(B) 0.2 H
(C) 0.4 H
(D) 0.8 H

B

Q. 30. The dimensions of magnetic flux are :
(A) [MLT−2A−2]
(B) [ML2T−2A−2]
(C) [ML2T−1A−2]
(D) [ML2T−2A−1]

D

Q. 31. A transformer is used to light a 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 amp, the efficiency of the transformer is approximately :
(A) 10%
(B) 30%
(C) 50%
(D) 90%

D

Q. 32. When the number of turns in a coil is doubled without any change in the length of the coil, its self inductance becomes :
(A) Four times
(B) Doubled
(C) Halved
(D) Unchanged

A

Q. 33. The core of a transformer is laminated because :
(A) Energy losses due to eddy currents may be minimised
(B) The weight of the transformer may be reduced
(C) Rusting of the core may be prevented
(D) Ratio of voltage in primary and secondary may be increased

A

Q. 34. The instantaneous values of alternating current and voltages in a circuit are given as
I = (1/√2 ) sin (100 πT) ampere
E = (1/√2 ) sin (100 πT + π/3) volt
The average power in Watts consumed in the circuit is :
(A) √3/4
(B) 1/2
(C) 1/8
(D) 1/4

C

Q. 35. In an AC generator, a coil with N turns all of the same area A and total resistance R, rotates with frequency ω in a magnetic field B. The maximum value of emf generated in the coil will be :
(A) NABRω
(B) NAB
(C) NABR
(D) NABω

D

Q. 36. In an A.C. circuit the current :
(B) Always lags behind the voltage
(C) Is always in phase with the voltage
(D) May lead or lag behind or be in phase with the voltage

D

Q. 37. An electric dipole is placed at an angle of 30° with an electric field intensity 2.0 × 105 N/C. It experiences a torque equal to 4 N m. The charge on the dipole, if the dipole length is 2 cm, is :
(A) 8 mC
(B) 2 mC
(C) 5 mC
(D) 7 μC

B

Q. 38. An electric dipole is kept in non-uniform electric field. It experiences
(A) A force and a torque
(B) A force but not a torque
(C) A torque but not a force
(D) Neither a force nor a torque

A

Q. 39. If a unit positive charge is taken from one point to another over an equipotential surface, then :
(A) Work is done on the charge
(B) Work is done by the charge
(C) Work done is constant
(D) No work is done

D

Q. 40. When one electron is taken towards the other electron, then the electric potential energy of the system
(A) Decreases
(B) Increases
(C) Remains unchanged
(D) Becomes zero

B

Q. 41. A charge of 40μC is given to a capacitor having capacitance C =10μF. The stored energy in ergs is :
(A) 80×10−6
(B) 800
(C) 80
(D) 8000

B

Q. 42. If the distance between parallel plates of a capacitor is halved and dielectric constant is doubled then the capacitance :
(A) Decreases two times
(B) Increases two times
(C) Increases four times
(D) Remain the same

C

Q. 43. A potentiometer wire has length 4 m and resistance 8 Ω. The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2V, so as to get a potential gradient 1 mV per cm on the wire is :
(A) 44 Ω
(B) 48 Ω
(C) 32 Ω
(D) 40 Ω

C

Q. 44. See the electric circuit shown in this Figure. Which of the following equations is a correct equation for it?

(A) ε1– (i1+i2)R + i1r1 = 0
(B) ε1– (i1+i2)R – i1r1 = 0
(C) ε2– i2r2– ε1– i1r1 = 0
(D) –ε1– (i1+i2)R + i2r2 = 0

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): Induction furnace uses eddy current for preparation of alloys, by melting the constituent metals.
Reason (R): Eddy currents are undesirable since they heat up the core and dissipate electrical energy in the form of heat.

B

Q. 46. Assertion (A): Whenever there is change in magnetic flux there is induced E.M.F. in a loop.
Reason (R): Whenever there is change in flux there is induced current in a loop.

C

Q. 47. Assertion (A): Acceleration of a magnet falling through a long solenoid decreases.
Reason (R): The induced current produced in a circuit always flow in such direction that it opposes the change or the cause that produces it.

A

Q. 48. Assertion (A): An e.m.f. is induced by moving a conductor in a magnetic field.
Reason (R): An e.m.f is induced by changing the magnetic field.

B

Q. 49. Assertion (A): In an impedance diagram of LCR circuit, if XC > XL, φ is positive and when XC < XL, φ is negative.
Reason (R): Impedance diagram is a right angled triangle with Z as hypotenuse, R is along X-axis and XC – XL is along Y axis.

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. The value of A.C. domestic supply is 240 V and its amplitude is
(A) 240 V
(B) 340 V
(C) 440 V
(D) 140 V

B

Q. 51. In pure capacitive and inductive circuit, power dissipation
(A) Is maximum
(B) Is minimum
(C) 0
(D) Depends on the value the angular frequency of the supply voltage.

C

Case Study

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

Electric charge density is the electric charge per unit dimension. Electric charge may be distributed along the length, over the surface and in the volume of a conductor.
Surface charge density of a conductor is defined as the amount of charge distributed per unit surface area of the conductor. It is denoted by σ.
If Q amount charge is distributed over the surface of a conductor of total surface area A, then σ = Q/A. SI unit of surface charge density is C/m2 .
The dimension of electric charge is [TA] and the dimension of surface area is [L2].
So, the dimension of Surface charge density of a conductor is [L–2TA].
Let a conducting sphere of radius r have total charge Q on its surface. Now, the surface area of the sphere is A = 4πr2.
So, the surface charge density is σ = Q/4πr2. This is the formula for surface charge density of a sphere.
Surface charge density of a conducting spherical shell is also same as that of a conducting sphere of same radius and same charge. Since, the curvature of the surface of a sphere is same at every point on its surface, the surface charge density is constant at everywhere on the surface of sphere.
For a conductor of irregular shape, the surface area will be different at different points on its surface.
So, surface charge density will vary point to point on its surface. The value of surface charge density will be greater at that region where the curvature is greater. That means it will have greater surface charge density at its edges. So, there is no fixed formula for surface charge density of an irregular shaped conductor.

Q. 52. Surface charge density of a spherical conductor of radius 100 cm is 0.5 c/m2. The total charge on the surface is
(A) 6.25 × 104 C
(B) 6.25 C
(C) 0.625 C
(D) 12.5 C

B

Q. 53. Same amounts of charges are given to each of a sphere and a spherical shell having same radius.
The ratio of their surface charge densities is
(A) 2 : 1
(B) 1 : 2
(C) 1 : 1
(D) 1 : 4

C

Q. 54. Which of the following statement is correct?
(A) The value of surface charge density is greater at that region where the curvature is greater.
(B) The value of surface charge density is less at that region where the curvature is greater.
(C) The value of surface charge density does not depend on curvature of the surface.
(D) None of the above

A

Q. 55. Dimension of surface charge density is
(A) [L2TA]
(B) [L–2TA[
(C) [LT2A]
(D) [LT–2A]