# MCQ Questions Chapter 2 Electrostatic Potential and Capacitance Class 12 Physics

Please refer to MCQ Questions Chapter 2 Electrostatic Potential and Capacitance Class 12 Physics with answers provided below. These multiple-choice questions have been developed based on the latest NCERT book for class 12 Physics issued for the current academic year. We have provided MCQ Questions for Class 12 Physics for all chapters on our website. Students should learn the objective based questions for Chapter 2 Electrostatic Potential and Capacitance in Class 12 Physics provided below to get more marks in exams.

## Chapter 2 Electrostatic Potential and Capacitance MCQ Questions

Please refer to the following Chapter 2 Electrostatic Potential and Capacitance MCQ Questions Class 12 Physics with solutions for all important topics in the chapter.

MCQ Questions Answers for Chapter 2 Electrostatic Potential and Capacitance Class 12 Physics

Question. The potential of the electric field produced by point charge at any point (x, y, z) is given by V = 3x2 + 5, where x, y are in metres and V is in volts. The intensity of the electric field at (–2, 1, 0) is
(a) +17 V m–1
(b) –17 V m–1
(c) +12 V m–1
(d) –12 V m–1

C

Question. The potential of a large liquid drop when eight liquid drops are combined is 20 V. Then the potential of each single drop was
(a) 10 V
(b) 7.5 V
(c) 5 V
(d) 2.5 V

C

Question. Two capacitors of capacities 1 μF and C μF are connected in series and the combination is charged to a potential difference of 120 V. If the charge on the combination is 80 μC, the energy stored in the capacitor of capacity C in mJ is
(a) 1800
(b) 1600
(c) 14400
(d) 7200

B

Question. A hollow conducting sphere is placed in an electric field produced by a point charge placed at P as shown in figure. Let VA, VB, VC be the potentials at points A, B and C respectively. Then

(a) VC > VB
(b) VB > VC
(c) V> VB
(d) VA = VC

D

Question. Three charges, each +q, are placed at the corners of an isosceles triangle ABC of sides BC and AC, 2a. D and E are the midpoints of BC and CA. The work done in taking a charge Q from D to E is

(a) 3qQ/8π∈0a
(b) qQ/4π∈0a
(c) zero
(d) 3qQ/4π∈0a

C

Question. The capacitance of a parallel plate capacitor with air as dielectric is C. If a slab of dielectric constant K and of the same thickness as the separation between the plates is introduced so as to fill (1/4)th of the capacitor (shown in figure), then the new capacitance is

B

Question. The capacity of a capacitor is 4 × 10–6 F and its potential is 100 V. The energy released on discharging it fully will be
(a) 0.02 J
(b) 0.04 J
(c) 0.025 J
(d) 0.05 J

A

Question. A parallel plate capacitor has capacitance C. If it is equally filled with parallel layers of materials of dielectric constant K1 and K2 its capacity becomes C1. The ratio of C1 and C is

D

Question. A glass rod rubbed with silk is used to charge a gold leaf electroscope and the leaves are observed to diverge. The electroscope thus charged is exposed to X-rays for a short period. Then
(a) the divergence of leave will not affected
(b) the leaves will diverge further
(c) the leaves will collapse
(d) the leaves will melt

B

Question. A thin metallic spherical shell contains a charge Q on it. A point charge q is placed at the centre of the shell and another charge q1 is placed outside it as shown in the figure. All the three charges are positive.

The force on the charge at the centre is
(a) towards left
(b) towards right
(c) upward
(d) zero

D

Question. As shown in the figure, charges +q and –q are placed at the vertices B and C of an isosceles triangle. The potential at the vertex A is

B

Question. Two capacitors of capacities C and 2C are connected in parallel and then connected in series with a third capacitor of capacity 3C. The combination is charged with V volt. The charge on capacitor of capacity C is

A

Question. An infinite number of charge, each of charge 1 μC are placed on the x-axis with coordinates x = 1, 2, 4, 8,……∞. If a charge of 1 C is kept at the origin, then what is the net force acting on 1 C charge?
(a) 9000 N
(b) 12000 N
(c) 24000 N
(d) 36000 N

B

Question. If 1000 droplets each of potential 1 V and radius r are combined to form a big drop. Then, the potential of the drop as compared to small droplets will be
(a) 1000 V
(b) 800 V
(c) 100 V
(d) 20 V

C

Question. Four equal charges q each are placed at four corners of a square of side a each. Work done in carrying a charge –q from its centre to infinity is

D

Question. A cube of side l is placed in a uniform field E, where E = Ei. The net electric flux through the cube is
(a) zero
(b) l2E
(c) 4l2E
(d) 6l2E

A

Question. An electric dipole consists of two opposite charges of magnitude q = 1 × 10–6 C separated by 2.0 cm. The dipole is placed in an external field of 1 × 105 N C–1. What maximum torque does the field exert on the dipole? How much work must an external agent do to turn the dipole end to end, starting from position of alignment (q = 0°)?
(a) 4.4 × 106 N-m, 3.2 × 10–4 J
(b) –2 × 10–3 N-m, –4 × 103 J
(c) 4 × 103 N-m, 2 × 10–3 J
(d) 2 × 10–3 N-m, 4 × 10–3 J

Question. On moving a charge of 20 C by 2 cm, 2 J of work is done, then the potential difference between the points is
(a) 0.1 V
(b) 8 V
(c) 2 V
(d) 0.5 V

A

Question. The insulation property of air breaks down at 3 × 106 V m–1. The maximum charge that can be given to a sphere of diameter 5 m is nearly
(a) 2 × 10–2 C
(b) 2 × 10–3 C
(c) 2 × 10–4 C
(d) 2 × 10–5 C

B

Question. An arc of radius r carries charge. The linear density of charge is λ and the arc subtends an angle π/3 at the centre. What is electric potential at the centre?

C

Question. A neutral water molecule (H2O) in its vapour state has an electric dipole moment of magnitude 6.4 × 10–30 C-m. How far apart are the molecules centres of positive and negative charges?
(a) 4 m
(b) 4 mm
(c) 4 μm
(d) 4 pm

D

Question. The energy stored in the capacitor as shown in the figure (a) is 4.5 × 10–6 J. If the battery is replaced by another capacitor of 900 pF as shown in figure (b), then the total energy of system is

(a) 4.5 × 10–6 J
(b) 2.25 × 10–6 J
(c) zero
(d) 9 × 10–6 J.

B

Question. In nature, the electric charge of any system is always equal to
(a) half integral multiple of the least amount of charge
(b) zero
(c) square of the least amount of charge
(d) integral multiple of the least amount of charge.

D

Question. If the force exerted by an electric dipole on a charge q at a distance of 1 m is F, the force at a point 2 m away in the same direction will be
(a) F/2
(b) F/4
(c) F/6
(d) F/8

D

Question. A sample of HCl gas is placed in an electric field of 3 × 104 N C–1. The dipole moment of each HCl molecule is 6 × 10–30 C m. The maximum torque that can act on a molecule is
(a) 2 × 10–34 C2 N–1 m
(b) 2 × 10–34 N m
(c) 18 × 10–26 N m
(d) 0.5 × 1034 C–2 N m–1.

C

Question. An infinitely long thin straight wire has uniform linear charge density of 1/3 C m−1 . Then, the magnitude of the electric intensity at a point 18 cm away is (given e0 = 8.8 × 10–12 C2 N m–2)
(a) 0.33 × 1011 N C–1
(b) 3 × 1011 N C–1
(c) 0.66 × 1011 N C–1
(d) 1.32 × 1011 N C–1

A

Question. Two points charges –q and +q are located at points (0, 0, –a) and (0, 0, a) respectively. The electric potential at a point (0, 0, z), where z > a is

C

Question. Two point like charges Q1 and Q2 of whose strengths are equal in absolute value are placed at a certain distance from each other. Assuming the field strength to be positive in the positive direction of x-axis, the signs of the charges Q1 and Q2 for the graphs (field strength versus distance) shown in figure (1), (2), (3) and (4) are:

(a) Q1 positive, Q2 negative; both positive; Q1 negative, Q2 positive; both negative
(b) Q1 negative Q2 positive; Q1 positive, Q2 negative; both positive; both negative
(c) Q1 positive, Q2 negative; both negative; Q1 negative, Q2 positive; both negative
(d) both positive; Q1 positive, Q2 negative; Q1 negative, Q2 positive; both negative

A

Question. A solid spherical conductor of radius R has a spherical cavity of radius a (a < R) at its centre. A charge +Q is kept at the center. The charge at the inner surface, outer surface and at a position r(a < r < R) are respectively
(a) +Q, –Q, 0
(b) –Q, +Q, 0
(c) 0, –Q, 0
(d) +Q, 0, 0.

B

Question. A cylindrical capacitor has charge Q and length L. If both the charge and length of the capacitors are doubled, by keeping other parameters fixed, the energy stored in the capacitor
(a) remains same
(b) increases two times
(c) decreases two times
(d) increases four times.

B

Question. ABCD is a rectangle. At corners B, C and D of the rectangle are placed charges +10 × 10–12 C, –20 × 10–12 C and 10 × 10–12 C, respectively. Calculate the potential at the fourth corner. (The side AB = 4 cm and BC = 3 cm)
(a) 1.65 V
(b) 0.165 V
(c) 16.5 V
(d) 2.65 V

A

Question. The electric field intensity E , due to an electric dipole of moment p , at a point on the equatorial line is
(a) parallel to the axis of the dipole and opposite to the direction of the dipole moment p
(b) perpendicular to the axis of the dipole and is directed away from it
(c) parallel to the dipole moment
(d) perpendicular to the axis of the dipole and is directed towards it

A

Question. A parallel plate capacitor of capacitance 100 pF is to be constructed by using paper sheets of 1 mm thickness as dielectric. If the dielectric constant of paper is 4, the number of circular metal foils of diameter 2 cm each required for the purpose is
(a) 40
(b) 20
(c) 30
(d) 10

D

Assertion-Reason Questions

In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R). Choose the correct answer out of the following choices.
(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.

Question. Assertion (A): A capacitor can be given only a limited amount of charge.
Reason (R): After a limited value of charge, the dielectric strength of dielectric between the capacitor plates breaks down.

A

Question. Assertion (A): The capacitance of a conductor does not depend on the charge given to it.
Reason (R): The capacitance of a conductor depends only on geometry and size of conductor.

A

Question. Assertion (A): The potential of earth is assumed zero.
Reason (R): Earth is insulator and so earth can not hold any charge.

C

Question. Assertion (A): The capacitance of a parallel plate capacitor increases when a dielectric constant of medium between the plates.
Reason (R): Capacitance of a parallel plate capacitor is directly proportional to dielectric constant of medium between the plates.

A

Question. Assertion (A): The surface of a conductor is always an equipotential surface.
Reason (R): A conductor contains free electrons which can move freely to equalise the potential.

A

Question. Assertion (A): When a charged capacitor is filled completely with a metallic slab, its capacitance is increased by a large amount.
Reason (R): The dielectric constant for metal is infinite.

A

Question. Assertion (A): The capacitance of a parallel plate capacitor increases with increase of distance between the plates.
Reason (R): Capacitance of a parallel plate capacitor i.e., C ?

D

Question. Assertion (A): A point charges is placed at the centre of a sphere of radius R. The radius of sphere is increased to 2R, the electric flux through the surface will remain unchanged.
Reason (R): According to Gauss’s theorem the electric flux Ø = 1/E0 × charge enclosed by surface, is independent of the radius of spherical surface.

A

Question. Assertion (A): When charged capacitors are connected in parallel, the algebraic sum of charges remains constant but there is a loss of energy.
Reason (R): During sharing a charges, the energy conservation law does not hold.