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# CBSE Class 12 Physics MCQ With Answers

## Class 12 Physics MCQ

Physics is one of the toughest subjects for students. Preparing for Physics is not an easy task either. Preparing for your Physics paper requires consistency, hard work and some practice. For the practice part, you need not worry because here at Adda247 we got your back. We’re all aware of your difficulties in studying for the boards. To assist you in achieving your goals, we have compiled a list of MCQs that will assist you in preparing for the CBSE Class 12 Physics MCQ. This post also includes the solutions to the CBSE Class 12 Physics MCQs. Before you go, check out CBSE Class 12 Physics Important MCQ Questions With Answers, and best of luck with your CBSE Class 12 Physics test!

Class 12 Physics Answer Key 2023

## Class 12 Physics MCQ With Answer 2023

Q. Electric field at a point varies as r° for
(a) an electric dipole
(b) a point charge
(c) a plane infinite sheet of charge
(d) a line charge of infinite length

Answer: (c) a plane infinite sheet of charge

Q. A positively charged particle is released from rest in an uniform electric field. The electric potential energy of the charge
(a) remains a constant because the electric field is uniform.
(b) increases because the charge moves along the electric field.
(c) decreases because the charge moves along the electric field.
(d) decreases because the charge moves opposite to the electric field.

Answer: (c) decreases because the charge moves along the electric field.

Q. Figures show some equipotential lines distributed in space. A charged object is moved from point A to point B.
(a) The work done in Fig. (i) is the greatest.
(b) The work done in Fig. (ii) is least.
(c) The work done is the same in Fig. (i), Fig.(ii) and Fig. (iii).
(d) The work done in Fig. (iii) is greater than Fig. (ii) but equal to that in Fig. (i).

Answer: (c) The work done is the same in Fig. (i), Fig.(ii) and Fig. (iii).

Q. Equipotential at a great distance from a collection of charges whose total sum is not zero are approximately
(a) spheres
(b) planes
(c) paraboloids
(d) ellipsoids

Q. Two small spheres each carrying a charge q are placed r metre apart. If one of the spheres is taken around the other one in a circular path of radius r, the work done will be equal to
(a) force between them × r
(b) force between them × 2πr
(c) force between them/2πr
(d) zero

Q. The charge flowing in a conductor varies with time as :
q = αt +12 βt² + 16 γt³
Where α, β, γ are positive constants. Then the initial current (l) is given by the condition :
(a) l = α
(b) l = α²
(c) l = α-1
(d) None of these

Q. A capacitor has capacitance C and reactance X, if capacitance and frequency become double, then reactance will be
(a) 4X
(b) X/2
(c) X/4
(d) 2X

Q. Given below are two statements labelled as Assertion (A) and Reason (R)

Assertion : We cannot think of a magnetic field configuration with three poles
Reason : A bar magnet does exert a torque on itself due to its own field.

Select the most appropriate answer from the options given below:

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false.

(d) A is false and R is also false.

Answer: (b) Both A and R are true but R is not the correct explanation of A.

Q. The quantisation of charge implies

(a) charge can’t be destroyed

(b) charge exists on particles

(c) there is a minimum permissible charge on a particle

(d) charge, which is a fraction of coulomb on a particle

Q. The unit of electric dipole moment is

(a) newton

(b) coulomb

(d) debye

Q. Charge is the property associated with the matter due to which it produces and experiences

(a) electric effects only

(b) magnetic effects only

(c) both electric and magnetic effects

(d) None of these

Q.  An electric dipole of moment ?⃗  is placed in a uniform electric field ?⃗  . Then

(i) the torque on the dipole is ?⃗ ×E→

(ii) the potential energy of the system is ?⃗ .E→

(iii) the resultant force on the dipole is zero. Choose the correct option.

(a) (i), (ii) and (iii) are correct

(b) (i) and (iii) are correct and (ii) is wrong

(c) only (i) is correct

(d) (i) and (ii) are correct and (iii) is wrong

Q.  In a parallel plate capacitor, the capacity increases if

(a) area of the plate is decreased.

(b) distance between the plates increases.

(c) area of the plate is increased.

(d) dielectric constantly decreases.

Q. A parallel plate air capacitor is charged to a potential difference of V volts. After disconnecting the charging battery the distance between the plates of the capacitor is increased using an insulating handle. As a result the potential difference between the plates

(a) increases

(b) decreases

(c) does not change

(d) becomes zero

Q. Two spherical conductors each of capacity C are charged to potential V and -V. These are then connected by means of a fine wire. The loss of energy is

(a) zero

(b) ½ CV²

(c) CV²

(d) 2 CV²

Q. Two identical capacitors are joined in parallel, charged to a potential V, separated and then connected in series, the positive plate of one is connected to the negative of the other. Which of the following is true?

(a) The charges on the free plated connected together are destroyed.

(b) The energy stored in this system increases.

(c) The potential difference between the free plates is 2V.

(d) The potential difference remains constant.

Q. In a region, potential is represented by V(x,y,z)= 6x – 8xy – 8y + 6yz, where V is in volts and x,y,z are in metres. The electric force experienced by a charge of 2 coulomb situated at the point (1,1,1) is-

(a) 6√5 N

(b) 30 N

(c) 24 N

(d) 4√35 N

Q. 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.

Answer: (d) The electron will continue to move with uniform velocity along the axis of the solenoid.

Q. Which of the following is not correct about cyclotron?

(a) It is a machine to accelerate charged particles or ions to high energies.
(b) Cyclotron uses both electric and magnetic fields in combination to increase the energy of charged particles.
(c) The operation of the cyclotron is based on the fact that the time for one revolution of an ion is independent of its speed or radius of its orbit.
(d) The charged particles and ions in cyclotron can move on any arbitrary path.

Answer: (d) The charged particles and ions in cyclotron can move on any arbitrary path.

Q. Which of the following independent quantities is not used to specify the earth’s magnetic field?

(a) Magnetic declination (θ).

(b) Magnetic dip (δ).

(c) Horizontal component of earth’s field (BH).

(d) Vertical component of earth’s field (BV).

Q. Which of the following is correct about magnetic monopole?

(a) Magnetic monopole exists.

(b) Magnetic monopole does not exist.

(c) Magnetic monopoles have a constant value of monopole momentum.

(d) The monopole momentum increase due to an increase in its distance from the field.

Q. Which of the following is not showing the essential difference between electrostatic shielding by a conducting shell and magnetostatic shielding?

(a) Electrostatic field lines can end on charges and conductors have free charges.

(b) Magnetic field lines can end but conductors cannot end them.

(c) Lines of the magnetic field cannot end on any material and perfect shielding is not possible.

(d) Shells of high permeability materials can be used to divert lines of the magnetic field from the interior region.

Q. The permeability of a paramagnetic substance is:

(a) very large
(b) small but more than unity
(c) less than unity
(d) negative

Answer: (b) small but more than unity

Q. The vertical component of earth’s magnetic field . at a place is √3 times the horizontal component
the value of angle of dip at this place is
(a) 30°
(b) 45°
(c) 60°
(d) 90°

Q. At a given place on earth’s surface the horizontal component of earth’s magnetic field is 2 × 103-5 T and resultant magnetic field is 4 × 103-5 T. The angle of dip at this place is
(a) 30°
(b) 60°
(c) 90°
(d) 45°

Q. Which of the following property shows the property of ferromagnetic substances?
(a) The ferromagnetic property depends on temperature
(b) The ferromagnetic property does not depend on temperature.
(c) At high enough temperature ferromagnet becomes a diamagnet.
(d) At low temperature ferromagnet becomes a paramagnet.

Answer: (a) The ferromagnetic property depends on temperature

Q. The primary origin of magnetism lies in
(a) atomic current and intrinsic spin of electrons.
(b) polar and non polar nature of molecules.
(c) Pauli exclusion principle.
(d) electronegative nature of materials.

Answer: (a) atomic current and intrinsic spin of electrons.

Q. If the coil A is made to rotate about a vertical axis (Figure). No current flows in B if A is at rest. The current in coil A, when the current in B (at t = 0) is counter clockwise and the coil A is as shown at this instant, t = 0, is

(a) constant current clockwise.
(b) varying current clockwise.
(c) varying current counterclockwise.
(d) constant current counterclockwise.

Q. A cylindrical bar magnet is rotated about its axis (Figure). A wire is connected from the axis and is made to touch the cylindrical surface through a contact. Then

(a) a direct current flows in the ammeter A.
(b) no current flows through the ammeter A.
(c) an alternating sinusoidal current flows through the ammeter A with a time period T = 2πω
(d) a time varying non-sinusoidal current flows through the ammeter.

Answer: (b) no current flows through the ammeter A.

Q. Eddy currents do not cause
(a) damping
(b) heating
(c) sparking
(d) loss of energy

Q. The electric field intensity due to an infinite cylinder of radius R and having charge q per unit length at a distance rir r(r > R) from its axis is
(a) directly proportional to r².
(b) directly proportional to r3.
(c) inversely proportional to r.
(d) inversely proportional to r².

Answer: (d) inversely proportional to r².

Q. In an L.C.R. series a.c. circuit, the current
(a) is always in phase with the voltage
(b) always lags the generator voltage
(c) always leads the generator voltage
(d) None of these

Q. An LCR series circuit, connected to a source E, is at resonance. Then the voltage across
(a) R is zero
(b) R equals applied voltage
(c) C is zero
(d) L equals applied voltage

Answer: (b) R equals applied voltage

Q. The electric field inside a spherical shell of uniform surface charge density is
(a) zero.
(b) constant, less than zero.
(c) directly proportional to the distance from the centre.
(d) none of the these

Q. Given below are two statements labelled as Assertion (A) and Reason (R)

Assertion: In high latitudes one sees colourful curtains of light hanging down from high altitudes
Reason: The high energy charged particles from the sun are deflected to polar regions by the magnetic field of the earth

Select the most appropriate answer from the options given below:

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false.

(d) A is false and R is also false.

Answer: (a) Both A and R are true and R is the correct explanation of A

Q. Given below are two statements labelled as Assertion (A) and Reason (R)

Assertion: A capacitor is connected to a direct current source. Its reactance is infinite.
Reason: Reactance of a capacitor is given by χc = 1/ωC.

Select the most appropriate answer from the options given below:

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false.

(d) A is false and R is also false.

Answer: (a) Both A and R are true and R is the correct explanation of A

Q. The temperature coefficient of resistance of a wire is 0.00125° C-1. At 27°C, its resistance is 1Ω. The temperature of the wire at which its resistance becomes 2Ω is:
(a) 1400 K
(b) 854°C
(c) 1127 K
(d) 1154 K.

Q.The heating element of an electric heater should be made of a material that should have:
(a) low specific resistance and low melting point.
(b) high specific resistance and high melting point.
(c) high specific resistance and low melting point.
(d) low specific resistance and high melting point.

Answer: (a) low specific resistance and low melting point.

Q. The effective wattage of 60 W and 40 W lamps connected in: series is equal to:
(a) 24 W
(b) 20 W
(c) 100 W
(d) 80 W.

Q. The effective wattage of 60 W and 40 W lamps connected in: parallel is equal to:
(a) 24 W
(b) 20 W
(c) 100 W
(d) 80 W

Q. At resonance frequency the impedance in series LCR circuit is
(a) maximum
(b) minimum
(c) zero
(d) infinity

Q. At resonant frequency the current amplitude in series LCR circuit is
(a) maximum
(b) minimum
(c) zero
(d) infinity

Q. In tuning, we vary the capacitance of a capacitor in the tunning circuit such that the resonant frequency of the circuit becomes nearly equal to the frequency of the radio signal received. When this happens, the …A… with the frequency of the signal of the particular radio station in the circuit is maximum. Here A refers to
(a) resonant frequency
(b) impedance
(c) amplitude of the current
(d) reactance

Answer: (c) amplitude of the current

Q. What is the angle of dip at a place where the horizontal component of earth’s magnetic field is equal to the vertical component?
(a) 0°
(b) 30°
(c) 45°
(d) 90°

Q. Which of the following has a low value in ferrites?
(a) Conductivity
(b) Permeability
(c) Magnetic susceptibility
(d) All the above

Q. S.I. unit of flux is :
(a) Ohm
(b) Weber
(c) Tesla
(d) None

Q. The dimensional representation of magnetic flux density is :
(a) [MLT-2]
(b) [MLT-2A-1]
(c) [MLT-2A-2]
(d) [MT-2A-1]

Q. A loop, made of straight edges has six comers at A(0, 0, 0), B(L, 0, 0) C(L, L, 0), D(0, L, 0), E(0, L, L) and F(0,0, L). A magnetic field B = Bo (i+k)T is present in the region. The flux passing through the loop ABCDEFA (in that order) is

(a) BoL² Wb.
(b) 2BoL² Wb.
(c) √2BoL² Wb.
(d) 4BoL² Wb.

Q. An e.m.f is produced in a coil, which is not connected to an external voltage source. This is not due to
(a) the coil being in a time varying magnetic field.
(b) the coil moving in a time varying magnetic field.
(c) the coil moving in a constant magnetic field.
(d) the coil is stationary in external spatially varying magnetic field, which does not change with time.

Answer: (d) the coil is stationary in external spatially varying magnetic field, which does not change with time.

Q. Given below are two statements labelled as Assertion (A) and Reason (R)

Assertion(A) The field intensity in between such sheets having equal and opposite uniform surface densities of charge become constant.

Reason(R): The field intensity does not depend upon the distance between the thin sheet.

Select the most appropriate answer from the options given below:

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false.

(d) A is false and R is also false.

Answer: (a) Both A and R are true and R is the correct explanation of A

Q. Given below are two statements labelled as Assertion (A) and Reason (R)

Assertion : In series LCR resonance circuit, the impedance is equal to the ohmic resistance.
Reason: At resonance, the inductive reactance exceeds the capacitive reactance.

Select the most appropriate answer from the options given below:

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false.

(d) A is false and R is also false.

Answer: (b) Both A and R are true but R is not the correct explanation of A.

Q. Given below are two statements labelled as Assertion (A) and Reason (R)

Assertion : A capacitor is connected to a direct current source. Its reactance is infinite.
Reason : Reactance of a capacitor is given by χc = 1/ωC.

Select the most appropriate answer from the options given below:

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false.

(d) A is false and R is also false.

Answer: (a) Both A and R are true and R is the correct explanation of A

Q. The force per unit charge is known as
(a) electric flux
(b) electric field
(c) electric potential
(d) electric current

Q. Which of the following statements is not true about Gauss’s law?
(a) Gauss’s law is true for any closed surface.
(b) The term q on the right side side of Gauss’s law includes the sum of all charges enclosed by the surface.
(c) Gauss’s law is not much useful in calculating electrostatic field when the system has some symmetry.
(d) Gauss’s law is based on the inverse square dependence on distance contained in the coulomb’s law

Answer: (c) Gauss’s law is not much useful in calculating electrostatic field when the system has some symmetry.

Q. In a region of constant potential
(a) the electric field is uniform.
(b) the electric field is zero.
(c) there can be no charge inside the region.
(d) both (b) and (c) are correct.

Answer: (d) both (b) and (c) are correct.

Q. Consider a uniform electric field in the z-direction. The potential is a constant
(a) for any x for a given z
(b) for any y for a given z
(c) on the x-y plane for a given z
(d) all of these

Q. Which of the following colours of white light deviated most when passes through a prism?
(a) Red light
(b) Violet light
(c) Yellow light
(d) Both (a) and (b)

Q. The conduction current is same as displacement current when source is
(a) ac only
(b) dc only
(c) either ac or dc
(d) neither dc nor ac

Answer: (c) either ac or dc

Q. If a conductor has a potential V ≠ 0 and there are no charges anywhere else outside, then
(a) there must be charges on the surface or in¬side itself.
(b) there cannot be any charge in the body of the conductor.
(c) there must be charges only on the surface.
(d) both (a) and (b) are correct.

Answer: (c) there must be charges only on the surface.

Q. Alternating voltage (V) is represented by the equation
(a) V(t) = Vm eωt
(b) V(t) = Vm sin ωt
(c) V(t) = Vm cot ωt
(d) V(t) = Vm tan ωt

Answer: (b) V(t) = Vm sin ωt

Q. The mobility of conduction electrons is greater than that of holes since electrons is greater than that of holes since electrons.
(a) are negatively charged.
(b) are lighter
(c) require smaller energy for moving through the crystal lattice.
(d) Undergo smaller number of collisions.

Answer: (c) require smaller energy for moving through the crystal lattice.

Q. Mirage is a phenomenon due to
(a) refraction of light
(b) reflection of light
(c) total internal reflection of light
(d) diffraction of light.

Answer: (c) total internal reflection of light

Q. Photoelectrons are being obtained by irradiating zinc by a radiation of 3100 Å. In order to increase the kinetic energy of ejected photoelectrons.
(a) the intensity of radiation should be increased.
(b) the wave length of radiation should be increased.
(c) the wavelength of radiation should be decreased.
(d) both wavelength and intesity of radiation should be increased.

Q. In a pure capacitive circuit if the frequency of ac source is doubled, then its capacitive reactance will be
(a) remains same
(b) doubled
(c) halved
(d) zero

Q. If the conductivity of a semiconductor is only due to break of the covalent band due to the thermal excitation, then the semiconductor is called:
(a) intrinsic
(b) extrinsic
(c) Acceptor
(d) none of these

Q. If a variable frequency ac source is connected to a capacitor then with decrease in frequency the displacement current will
(a) increase
(b) decrease
(c) remains constant
(d) first decrease then increase

Q. Direction of current induced in a wire moving in a magnetic field is found using
(a) Fleming’s left hand rule
(b) Fleming’s right hand rule
(c) Ampere’s rule
(d) Right hand clasp rule

Answer: (b) Fleming’s right hand rule

Q. A solenoid is connected to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, the current will
(a) increase
(b) decrease
(c) remain same
(d) first increase then decrease

## Class 12 Physics MCQs for term 1 Expected Question

Check All Answer Keys for CBSE Class

## Class 12 Physics MCQs Sample Paper for Practice

SECTION A

Q1. On charging by conduction, mass of a body may

चालन द्वारा चार्ज करने पर, किसी पिंड का द्रव्यमान हो सकता है

(a)increase

वृद्धि
(b) decreases

घटता है
(c) increase or decrease

वृद्धि या कमी
(d) None of these

इनमें से कोई नहीं

Q2. Quantisation of charge implies

चार्ज की मात्रा का तात्पर्य है

(a) charge cannot be destroyed

चार्ज नष्ट नहीं किया जा सकता
(b) charge exists on particles

कणों पर चार्ज मौजूद है
(c) there is a minimum permissible charge on a particle

एक कण पर न्यूनतम अनुमेय चार्ज है

(d) charge, which is a fraction of a coulomb is not possible.

चार्ज, जो एक कूलम्ब का एक अंश है संभव नहीं है।

Q 3. If an object possesses an electric charge, it is said to be
electrified or … A … When it has no charge, it is said to
be … B … Here, A and B refer to

यदि किसी वस्तु में विद्युत आवेश होता है, तो उसे कहा जाता है

विद्युतीकृत या … A … जब इसका कोई शुल्क नहीं है, तो इसे कहा जाता है

B… B … यहां, A और B है

(a) charged, neutral

चार्ज, तटस्थ
(b) neutral, charged

तटस्थ, चार्ज
(c) discharged, charged

चार्ज नहीं, चार्ज

(d) active, reactive

सक्रिय, प्रतिक्रियाशील

Question 4.
Two capacitors of 3 µF and 6 µF are connected in series with a battery of P.d. 12 V. The P.d. across 3µF and 6µF
capacitors respectively will be :

3 µF और 6 µF के दो कैपेसिटर P.d की बैटरी के साथ श्रृंखला में जुड़े हुए हैं। 12 वी. पी.डी. 3μF और 6μF . के पार

कैपेसिटर क्रमशः होंगे:

(a) 8 V, 4 V
(b) 6 V, 6 V
(c) 4 V, 8 V
(d) 9 V, 3 V

Question 5.
An electric charge of 425 f µC is removed from a fully charged capacitor of capacitance 8.5µF. Its potential will be lowered by:

8.5μF की धारिता के पूर्ण आवेशित संधारित्र से 425 f µC का विद्युत आवेश हटा दिया जाता है। इसकी क्षमता कम हो जाएगी:
(a) 75 V
(b) 100 V
(c) 85 V
(d) 50 V

Question 6.
Kirchhoffs first and second laws for electrical circuits are consequences of:

विद्युत परिपथों के लिए किरचॉफ के पहले और दूसरे नियम के परिणाम हैं:

(a) conservation of energy

ऊर्जा का संरक्षण
(b) conservation of electrical charge and energy respectively

क्रमशः विद्युत आवेश और ऊर्जा का संरक्षण
(c) conservation of electric charge

विद्युत प्रभार का संरक्षण

(d) neither conservation of energy nor electric charge

न तो ऊर्जा का संरक्षण और न ही विद्युत प्रभार

Question 7.
A 5 A fuse wire can with stand a maximum power of 1 W in circuit. The resistance of the fuse wire is:

एक 5A फ्यूज तार सर्किट में अधिकतम 1 डब्ल्यू की शक्ति के साथ खड़ा हो सकता है। फ्यूज तार का प्रतिरोध है :
(a) 0.2 Ω
(b) 5 Ω
(c) 0.4 Ω
(d) 0.04 Ω

Question 8.

A dielectric is placed in between the two parallel plates of a capacitor as shown in the figure. The dielectric constant of the dielectric being K. If the initial capacity is C, then the new capacity will be:

जैसा कि चित्र में दिखाया गया है, एक संधारित्र की दो समानांतर प्लेटों के बीच एक परावैद्युत रखा जाता है। ढांकता हुआ स्थिरांक K है। यदि प्रारंभिक क्षमता C है, तो नई क्षमता होगी:

(a) (K + l).C
(b) K.C
(c) (K+1)2 C
(d) (k – l) C

Question 9.
How much force will be experienced by a moving charge in a magnetic field? The symbols have their usual meanings.
(a) F⃗  = q(v⃗ .B⃗ )
(b) F⃗  = q(v⃗ .B⃗ )
(c) F⃗  = q2(v⃗ ×B⃗ )
(d) F⃗  = q(v⃗ ×B⃗ )

चुंबकीय क्षेत्र में गतिमान आवेश द्वारा कितना बल अनुभव किया जाएगा? प्रतीकों के अपने सामान्य अर्थ होते हैं।

(a) F⃗  = q(v⃗ .B⃗ )
(b) F⃗  = q(v⃗ .B⃗ )
(c) F⃗  = q2(v⃗ ×B⃗ )
(d) F⃗  = q(v⃗ ×B⃗ )

Question 10.
Which of the following is not a unit of magnetic induction?

निम्नलिखित में से कौन चुंबकीय प्रेरण की इकाई नहीं है?
(a) gauss
(b) tesla
(c) oersted
(d) weber/metre²

Question 11.
The magnetic field produced by an / meter long straight (x cry thin) current (I) carrying conductor at any point on itself is :

एक / मीटर लंबे सीधे (x क्राई थिन) विद्युत (I) कंडक्टर को किसी भी बिंदु पर ले जाने से उत्पन्न चुंबकीय क्षेत्र है:

(a) zero

शून्य
(b) infinite

अनंत
(c) µ0l4πl
(d) µ0l2πl

Question 12.
A charge + q is sent through a magnetic field. The force acting on it is maximum when the angle between the direction of motion of the charged particle and the magnetic field :

एक चार्ज q एक चुंबकीय क्षेत्र के माध्यम से भेजा जाता है। उस पर कार्य करने वाला बल अधिकतम होता है जब आवेशित कण की गति की दिशा और चुंबकीय क्षेत्र के बीच का कोण होता है:

(a) 0°
(b) 45°
(c) 90°
(d) 180°

Question 13.
An electron having mass ‘m’ and Kinetic energy E enters in uniform magnetic field B perpendicular, then its frequency will be:

द्रव्यमान ‘m’ और गतिज ऊर्जा E वाला एक इलेक्ट्रॉन एकसमान चुंबकीय क्षेत्र B में लंबवत प्रवेश करता है, तो इसकी आवृत्ति होगी:

(a) eEqmB
(b) 2πmeB
(c) eB2πm
(d) 2meBE

Question 14.
A wire of length 2 metre carries a current 1 ampere, is bent to form a circle. The magnetic moment of the coil is :

2 मीटर लंबाई के एक तार में 1 एम्पीयर की धारा प्रवाहित होती है, जिसे एक वृत्त बनाने के लिए मोड़ा जाता है। कुंडल का चुंबकीय आघूर्ण है:

(a) 2π
(b) π/2
(c) π/4
(d) 1/π

Question 15.
The magnetic field of a given length of a ware for single turn coil at its centre is B. Then. Its value for two turns of coil will be :

इसके केंद्र में सिंगल टर्न कॉइल के लिए दी गई लंबाई के बर्तन का चुंबकीय क्षेत्र B होता है। कुण्डली के दो फेरों के लिए इसका मान होगा :

(a) B/4
(b) B/2
(c) 4B
(d) 2B

SECTION B

Question 16.
On quadrupling the moment of inertia of a magnet, its frequency of oscillation will become:

चुम्बक के जड़त्व आघूर्ण को चौगुना करने पर उसके दोलन की आवृत्ति हो जाएगी :

(a) half

आधा
(b) double

दोहरा

(c) four times

चार गुना

(d) one-fourth

एक चौथाई

Question 17.
n resistances, each of R Ω, are connected in parallel gives an equivalent resistance of R Ω. If these resistances were , connected in series, the combination would have a resistance in Ω is equal to

n प्रतिरोध, R में से प्रत्येक, समानांतर में जुड़े हुए हैं, R के बराबर प्रतिरोध देता है। यदि इन प्रतिरोधों को श्रेणीक्रम में जोड़ा जाता है, तो संयोजन का प्रतिरोध Ω के बराबर होता है

(a) n²R
(b) R/n²
(c) R/n
(d) nR

Question 18
To convert galvanometer into voltmeter one should connect :

गैल्वेनोमीटर को वोल्टमीटर में बदलने के लिए कनेक्ट करना चाहिए:

(a) high resistance in series with galvanometer

गैल्वेनोमीटर के साथ श्रृंखला में उच्च प्रतिरोध
(b) low resistance in series with galvanometer

गैल्वेनोमीटर के साथ श्रृंखला में कम प्रतिरोध
(c) high resistance in parallel with galvanometer

गैल्वेनोमीटर के समानांतर में उच्च प्रतिरोध
(d) low resistance in parallel with galvanometer

गैल्वेनोमीटर के समानांतर में कम प्रतिरोध

Question 19.
A charge q moves in a region, where electric field E and magnetic field B both exist, then force on it is :

एक आवेश q उस क्षेत्र में गति करता है, जहाँ विद्युत क्षेत्र E और चुंबकीय क्षेत्र B दोनों मौजूद हैं, तो उस पर बल होगा:

(a) F⃗  = q(v⃗ ×B⃗ )
(b) F⃗  = q{E⃗ ×(v⃗  × B⃗ )}
(c) F⃗  = q(E⃗  + (B⃗  × v⃗ )
(d) F⃗  = q(B⃗  + (E⃗  ×v⃗ )

Question 20.
Isoclinic lines are the lines joining places with :

आइसोक्लिनिक रेखाएँ स्थानों को मिलाने वाली रेखाएँ हैं:

(a) equal dip

बराबर डिप्
(b) equal declination

समान गिरावट
(c) j equal dip and declination

जे बराबर डुबकी और गिरावट
(d) None of these

इनमें से कोई नहीं

Question 21.
Two identical bar magnets each of dipole moment p and length I are perpendicular to each other as shown in Fig. The dipole moment of the combination is:

द्विध्रुव आघूर्ण p और लंबाई I के दो समान छड़ चुम्बक एक दूसरे के लंबवत हैं जैसा कि चित्र में दिखाया गया है। संयोजन का द्विध्रुव आघूर्ण है:

(a) √2 p
(b) p√2
(c) P
(d) 2p

Question 22.
In a moving coil galvanometer, we use a radial magnetic field so that the galvanometer scale is :

एक गतिमान कुंडल गैल्वेनोमीटर में, हम एक रेडियल चुंबकीय क्षेत्र का उपयोग करते हैं ताकि गैल्वेनोमीटर का पैमाना हो:

(a) exponential

घातीय
(b) linear

रैखिक

(c) algebraic

रैखिक

(d) logarithmic

लॉगरिदमिक

Q.23. The north pole of a long bar magnet was pushed slowly into a short solenoid connected to a short galvanometer. The magnet was held stationary for a few seconds with the north pole in the middle of the solenoid and then withdrawn rapidly. The maximum deflection of the galvanometer was observed when the magnet was

एक लंबी छड़ चुम्बक के उत्तरी ध्रुव को एक लघु गैल्वेनोमीटर से जुड़े लघु परिनालिका में धीरे-धीरे धकेला गया। चुंबक को कुछ सेकंड के लिए परिनालिका के बीच में उत्तरी ध्रुव के साथ स्थिर रखा गया और फिर तेजी से वापस ले लिया गया। गैल्वेनोमीटर का अधिकतम विक्षेपण तब देखा गया जब चुंबक था

(a) moving towards the solenoid

सोलेनोइड की ओर बढ़ रहा है

(b) moving into the solenoid

सोलेनोइड में जा रहा है

(c) at rest inside the solenoid

परिनालिका के अंदर आराम पर

(d) moving out of the solenoid

सोलेनोइड से बाहर निकलना

Question 24.
The force between two parallel wire 2 × 10-7 Nm-1, placed 1 m apart to each other in vacuum. The electric current flowing through the wires is:

दो समान्तर तार 2 × 10-7 Nm-1 के बीच का बल निर्वात में एक दूसरे से 1 मीटर की दूरी पर स्थित है। तारों से बहने वाली विद्युत धारा है:

(a) 1 A
(b) zero

शून्य
(c) 5 × 106 A
(d) 2 × 10-7 A

Q.25. The current flows from A to B is as shown in the figure. The direction of the induced current in the loop is

धारा A से B की ओर प्रवाहित होती है जैसा कि चित्र में दिखाया गया है। लूप में प्रेरित धारा की दिशा है
(a) clockwise.
दक्षिणावर्त।

(b) anti clock wise

वामावर्त।

(c) straight line.

सीधी रेखा

(d) no induced e.m.f. produced.

कोई प्रेरित ई.एम.एफ. उत्पादित

Q.26. In a coil of self-induction 5 H, the rate of change of current is 2 As-1. Then emf induced in the coil is

. स्व-प्रेरण 5H की एक कुण्डली में धारा के परिवर्तन की दर 2 As-1 है। तब कुंडली में प्रेरित emf है
(a) 10 V
(b) -10 V
(c) 5 V
(d) -5 V

Q.27. The magnetic flux linked with a coil of N turns of area of cross section A held with its plane parallel to the field B is

क्षेत्र B के समानांतर अपने विमान के साथ रखे क्रॉस सेक्शन ए के क्षेत्र के N मोड़ के कॉइल से जुड़ा चुंबकीय प्रवाह है

Question 28 Given below are two statements labelled as Assertion and Reason

नीचे दिए गए दो कथनों को अभिकथन और कारण के रूप में लेबल किया गया है

Assertion : In a purely inductive or capacitive circuit, the current is referred to as wattless current.

अभिकथन: विशुद्ध रूप से आगमनात्मक या कैपेसिटिव सर्किट में, विद्युत को वाटलेस विद्युत कहा जाता है।
Reason: No power is dissipated in a purely inductive or capacitive circuit even though a current is flowing in the circuit.

कारण: विशुद्ध रूप से आगमनात्मक या कैपेसिटिव सर्किट में कोई शक्ति समाप्त नहीं होती है, भले ही सर्किट में विद्युत प्रवाहित हो।

Select the most appropriate answer from the options given below:

नीचे दिए गए विकल्पों में से सर्वाधिक उपयुक्त उत्तर का चयन कीजिए :

(a) Both A and R are true and R is the correct explanation of A

ए और आर दोनों सत्य हैं और आर ए की सही व्याख्या है

(b) Both A and R are true but R is not the correct explanation of A.

ए और आर दोनों सत्य हैं लेकिन आर ए की सही व्याख्या नहीं है।

(c) A is true but R is false.

ए सच है लेकिन आर झूठा है।

(d) A is false and R is also false.

ए झूठा है और आर भी झूठा है

Question 29 Given below are two statements labelled as Assertion and Reason

नीचे दिए गए दो कथनों को अभिकथन और कारण के रूप में लेबल किया गया है

Assertion : The power in an ac circuit is minimum if the circuit has only a resistor.

अभिकथन: एक एसी सर्किट में शक्ति न्यूनतम होती है यदि सर्किट में केवल एक प्रतिरोधक होता है।

Reason: Power of a circuit is independent of the phase angle.

कारण: सर्किट की शक्ति चरण कोण से स्वतंत्र होती है।

Select the most appropriate answer from the options given below:

नीचे दिए गए विकल्पों में से सर्वाधिक उपयुक्त उत्तर का चयन कीजिए :

(a) Both A and R are true and R is the correct explanation of A

ए और आर दोनों सत्य हैं और आर ए की सही व्याख्या है

(b) Both A and R are true but R is not the correct explanation of A.

ए और आर दोनों सत्य हैं लेकिन आर ए की सही व्याख्या नहीं है।

(c) A is true but R is false.

ए सच है लेकिन आर झूठा है।

(d) A is false and R is also false.

ए झूठा है और आर भी झूठा है

Question 30 Given below are two statements labelled as Assertion and Reason

नीचे दिए गए दो कथनों को अभिकथन और कारण के रूप में लेबल किया गया है

Assertion : When the frequency of the AC source in an LCR circuit equals the resonant frequency, the reactance of the circuit is zero, and so there is no current through the inductor or the capacitor.

अभिकथन: जब LCR सर्किट में AC स्रोत की आवृत्ति गुंजयमान आवृत्ति के बराबर होती है, तो सर्किट की प्रतिक्रिया शून्य होती है, और इसलिए प्रारंभ करनेवाला या संधारित्र के माध्यम से कोई धारा नहीं होती है।

Reason : The net current in the inductor and capacitor is zero.

कारण: प्रारंभ करनेवाला और संधारित्र में शुद्ध धारा शून्य है।

Select the most appropriate answer from the options given below:

नीचे दिए गए विकल्पों में से सर्वाधिक उपयुक्त उत्तर का चयन कीजिए :

(a) Both A and R are true and R is the correct explanation of A

ए और आर दोनों सत्य हैं और आर ए की सही व्याख्या है

(b) Both A and R are true but R is not the correct explanation of A.

ए और आर दोनों सत्य हैं लेकिन आर ए की सही व्याख्या नहीं है।

(c) A is true but R is false.

ए सच है लेकिन आर झूठा है।

(d) A is false and R is also false.

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.

Q31. The graph drawn between V are r for a non-conducting charged solid sphere of radius R for r < R will be :

त्रिज्या R के एक अचालक आवेशित ठोस गोले के लिए V के बीच खींचा गया ग्राफ r <R के लिए होगा:

(a) straight line

सीधी रेखा
(b) parabola

परवलय
(c) hyperbola

अतिशयोक्ति

(d) None of these

Case Study Question :

When an insulator is placed in an external field, the dipoles become aligned. Induced surface charges on the insulator establish a polarization field Ēi in its interior. The net field Ē in the insulator is the vector sum of Ē, and Ēi as shown in the figure.

जब एक इन्सुलेटर को बाहरी क्षेत्र में रखा जाता है, तो द्विध्रुव संरेखित हो जाते हैं। इन्सुलेटर पर प्रेरित सतह शुल्क इसके आंतरिक भाग में एक ध्रुवीकरण क्षेत्र Ēi स्थापित करते हैं। इन्सुलेटर में शुद्ध क्षेत्र , का वेक्टर योग है, और Ēi जैसा कि चित्र में दिखाया गया है।

On the application of external electric field, the effect of aligning the electric dipoles in the insulator is called
polarisation and the field Ē; is known as the polarisation field.
The dipole moment per unit volume of the dielectric is known as polarisation (P).
For linear isotropic dielectrics, P =χE, where χ = electrical susceptibility of the dielectric medium.

बाह्य विद्युत क्षेत्र के अनुप्रयोग पर, विद्युत द्विध्रुवों को कुचालक में संरेखित करने के प्रभाव को कहा जाता है

ध्रुवीकरण और क्षेत्र Ē; ध्रुवीकरण क्षेत्र के रूप में जाना जाता है।

ढांकता हुआ का प्रति इकाई आयतन द्विध्रुवीय क्षण को ध्रुवीकरण (P) के रूप में जाना जाता है।

रैखिक आइसोट्रोपिक डाइलेक्ट्रिक्स के लिए, पी = χ ई, जहां χ = ढांकता हुआ माध्यम की विद्युत संवेदनशीलता।

Q32 Which among the following is an example of polar molecule?

निम्नलिखित में से कौन ध्रुवीय अणु का उदाहरण है?
(2) O₂
(b) H
(c) N2
(d) HCI

Q33 When air is replaced by a dielectric medium of constant K, the maximum force of attraction between two charges separated by a distance

जब हवा को निरंतर K के परावैद्युत माध्यम से प्रतिस्थापित किया जाता है, तो दूरी द्वारा अलग किए गए दो आवेशों के बीच आकर्षण का अधिकतम बल

(a) increases K times

K गुना बढ़ जाता है
(b) remains unchanged

अपरिवर्तित रहता है
(c) decreases K times

K गुना घट जाती है
(d) increases 2K times.

2K गुना बढ़ जाता है।

Q34 Which of the following is a dielectric?

निम्नलिखित में से कौन एक ढांकता हुआ है?
(a) Copper

कॉपर
(b) Glass

ग्लास
(c) Antimony (Sb)

सुरमा (एसबी)

(d) None of these

इनमें से कोई नहीं

Q35 For a polar molecule, which of the following statements is true ?

एक ध्रुवीय अणु के लिए, निम्नलिखित में से कौन सा कथन सत्य है?
(a) The centre of gravity of electrons and protons coincide.

इलेक्ट्रॉनों और प्रोटॉन के गुरुत्वाकर्षण का केंद्र मेल खाता है।
(b) The centre of gravity of electrons and protons do not coincide.

इलेक्ट्रॉनों और प्रोटॉन के गुरुत्वाकर्षण का केंद्र मेल नहीं खाता है।

(c) The charge distribution is always symmetrical.

चार्ज वितरण हमेशा सममित होता है।

(d) The dipole moment is always zero.

द्विध्रुव आघूर्ण सदैव शून्य होता है।

S1. (Ans) (c)

S2 (Ans) (c)

S3 (Ans) (b)

S4 (Ans) (b)

S5 (Ans) (a)

S6 (Ans) (d)

S7 (Ans) (c)

S8 (Ans) (a)

S9 (Ans) (b)

S10 (Ans) (c)

S11 (Ans) (a)

S12 (Ans) (c)

S13 (Ans) (c)

S14 (Ans) (c)

S15 (Ans) (b)

Section-B

S16 (Ans) (d)

S17 (Ans) (c)

S18 (Ans) (a)

S19 (Ans) (d)

S20 (Ans) (b)

S21 (Ans) (d)

S22 (Ans) (b)

S23 (Ans) (b)

S24 (Ans) (a)

S25 (Ans) (a)

S26 (Ans) (d)

S27 (Ans) (c)

S28 (Ans) (a)

S29 (Ans) (b)

Section-C

S30 (Ans) (a)

S31 (Ans) (b)

S32 (d)
S33 (c)

S34 (b)
S35 (b)

## CBSE Class 12 Physics MCQs 2023 QNA

### Why is physics so challenging?

Physics is tough for students because they must compete against a variety of representations such as experiments, formulas and computations, graphs, and conceptual explanations all at once.

### In physics, what do we primarily study?

Quantum mechanics is used to study very small objects, while general relativity is used to study the entire cosmos.

### In layman’s terms, what is physics?

Physics is the study of energy and matter in space and time, as well as their interrelationships.

### Is physics a type of mathematics?

Physics and mathematics have always been intertwined, and many historical figures were both physicists and mathematicians.

### Who discovered gravity?

Sir Isaac Newton discovered gravity.

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## FAQs

### Why is physics so challenging?

Physics is tough for students because they must compete against a variety of representations such as experiments, formulas and computations, graphs, and conceptual explanations all at once.

### In physics, what do we primarily study?

Quantum mechanics is used to study very small objects, while general relativity is used to study the entire cosmos.

### In layman's terms, what is physics?

Physics is the study of energy and matter in space and time, as well as their interrelationships.

### Is physics a type of mathematics?

Physics and mathematics have always been intertwined, and many historical figures were both physicists and mathematicians.

### Who discovered gravity?

Sir Isaac Newton discovered gravity.

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