# MCQs For NCERT Class 12 Physics Chapter 2 Electrostatic Potential and Capacitance

Please refer to the MCQ Questions for Class 12 Physics Chapter 2 Electrostatic Potential and Capacitance with Answers. The following Electrostatic Potential and Capacitance Class 12 Physics MCQ Questions have been designed based on the latest syllabus and examination pattern for Class 12. Our experts have designed MCQ Questions for Class 12 Physics with Answers for all chapters in your NCERT Class 12 Physics book.

## Electrostatic Potential and Capacitance Class 12 MCQ Questions with Answers

See below Electrostatic Potential and Capacitance Class 12 Physics MCQ Questions, solve the questions and compare your answers with the solutions provided below.

Question. Energy per unit volume for a capacitor having area A and separation d kept at potential difference V is given by
(a) 1/2 εV2/d2
(b) 1/2ε.V2/d2
(c) 1/2 CV2
(d) Q2/2C

A

Question. A capacitor is charged with a battery and energy stored is U. After disconnecting battery another capacitor of same capacity is connected in parallel to the first capacitor. Then energy stored in each capacitor is
(a) U/2
(b) U/4
(c) 4U
(d) 2U

B

Question. In a certain region of space with volume 0.2 m3, the electric potential is found to be 5 V throughout. The magnitude of electric field in this region is
(a) zero
(b) 0.5 N/C
(c) 1 N/C
(d) 5 N/C

A

Question. A bullet of mass 2 g is having a charge of 2 mC. Through what potential difference must it be accelerated, starting from rest, to acquire a speed of 10 m/s ?
(a) 5 kV
(b) 50 kV
(c) 5 V
(d) 50 V

B

Question. The electric potential at a point in free space due to charge Q coulomb is Q × 1011 volts. The electric field at that point is   C
(a) 4pe0Q × 1020 volt/m
(b) 12pe0Q × 1022 volt/m
(c) 4pe0Q × 1022 volt/m
(d) 12pe0Q × 1020 volt/m

C

Question. A short electric dipole has a dipole moment of 16 × 10–9 C m. The electric potential due to the dipole at a point at a distance of 0.6 m from the centre of the dipole, situated on a line making an angle of 60° with the dipole axis is (1/4πε0 = 9×109 Nm2/C2 )
(a) 50 V
(b) 200 V
(c) 400 V
(d) zero

B

Question. Two metal spheres, one of radius R and the other of radius 2R respectively have the same surface charge density s. They are brought in contact and separated.
What will be the new surface charge densities on them?
(a) σ1 = 5/6σ ,σ2 =5/2σ
(b) σ1 = 5/2σ ,σ2 =5/6σ
(c) σ1 = 5/2σ ,σ2 =5/3σ
(d) σ1 = 5/3σ ,σ2 =5/6σ

D

Question. Four point charges –Q, –q, 2q and 2Q are placed, one at each corner of the square. The relation between Q and q for which the potential at the centre of the square is zero is
(a) Q = –q
(b) Q == − 1/q
(c) Q = q
(d) Q = 1/q

A

Question. If potential (in volts) in a region is expressed as V(x, y, z) = 6xy – y + 2yz, the electric field (in N/C) at point (1, 1, 0) is
(a) -(2î +3j + k)
(b) -(6i + 9j+k)
(c) -(3i+5j+3k)
(d) −(6i + 5j+2k)

D

Question. A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system
(a) decreases by a factor of 2
(b) remains the same
(c) increases by a factor of 2
(d) increases by a factor of 4.

A

Question. A parallel plate air capacitor of capacitance C is connected to a cell of emf V and then disconnected from it. A dielectric slab of dielectric constant K, which can just fill the air gap of the capacitor, is now inserted in it. Which of the following is incorrect?
(a) The change in energy stored is 1/2CV2(1/K-1).
(b) The charge on the capacitor is not conserved.
(c) The potential difference between the plates decreases K times.
(d) The energy stored in the capacitor decreases K times.

B

Question. A parallel plate capacitor has a uniform electric field E in the space between the plates. If the distance between the plates is d and area of each plate is A, the energy stored in the capacitor is
(a) 1/2 ε0 E2

C

Question. In a region, the 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 point (1, 1, 1) is
(a) 6 5N
(b) 30 N
(c) 24 N
(d) 4 √35N

D

Question. The electric potential V at any point (x, y, z), all in metres in space is given by V = 4×2 volt. The electric field at the point (1, 0, 2) in volt/meter, is
(a) 8 along negative X-axis
(b) 8 along positive X-axis
(c) 16 along negative X-axis
(d) 16 along positive X-axis

A

Question. Charge q2 is at the centre of a circular path with radius r. Work done in carrying charge q1, once around this equipotential path, would be
(a) 1 /4πε0 x q1q2 /r2
(b) 1 /4πε0 x q1q2 /r
(c) zero
(d) infinite.

C

Question. Identical charges (–q) are placed at each corners of cube of side b, then electrostatic potential energy of charge (+q) which is placed at centre of cube will be
(a) −4√2 q/πε0b
(b) −8√2 q/πε0b
(c) −4q/√3πε0b
(d) −8√2 q/4πε0b

C

Question. In bringing an electron towards another electron, the electrostatic potential energy of the system
(a) becomes zero
(b) increases
(c) decreases
(d) remains same

B

Question. Two metallic spheres of radii 1 cm and 3 cm are given charges of –1 × 10–2 C and 5 × 10–2 C, respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is
(a) 2 × 10–2 C
(b) 3 × 10–2 C
(c) 4 × 10–2 C
(d) 1 × 10–2 C

B

Question. An electric dipole of dipole moment p is aligned parallel to a uniform electric field E. The energy required to rotate the dipole by 90° is
(a) p2E
(b) pE
(c) infinity
(d) pE2

B

Question. An electric dipole of moment p is placed in an electric field of intensity E. The dipole acquires a position such that the axis of the dipole makes an angle q with the direction of the field. Assuming that the potential energy of the dipole to be zero when q = 90°, the torque and the potential energy of the dipole will respectively be   A
(a) pEsinq, –pEcosq
(b) pEsinq, –2pEcosq
(c) pEsinq, 2pEcosq
(d) pEcosq, –pEsinq

Question. An electric dipole of moment p is lying along a uniform electric field E. The work done in rotating the dipole by 90° is
(a) pE
(b) 2pE
(c) pE/2
(d) 2pE

A

Question. An electric dipole has the magnitude of its charge as q and its dipole moment is p. It is placed in a uniform electric field E. If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively
(a) 2q · E and minimum
(b) q · E and p · E
(c) zero and minimum
(d) q · E and maximum

C

Question. There is an electric field E in x-direction. If the work done on moving a charge of 0.2 C through a distance of 2 m along a line making an angle 60° with x-axis is 4 J, then what is the value of E ?   B
(a) 5 N/C
(b) 20 N/C
(c) 3 N/C
(d) 4 N/C

Question. An electric dipole of moment p is placed in the position of stable equilibrium in uniform electric field of intensity E. This is rotated through an angle q from the initial position. The potential energy of the electric dipole in the final position is   B
(a) –pE cosq
(b) pE(1 – cosq)
(c) pE cosq
(d) pE sinq

Question. A parallel plate condenser with oil between the plates (dielectric constant of oil K = 2) has a capacitance C. If the oil is removed, then capacitance of the capacitor becomes   D
(a) C/√2
(b) 2C
(c) 2C
(d) C/2

Question. Three capacitors each of capacitance C and of breakdown voltage V are joined in series.
The capacitance and breakdown voltage of the combination will be
(a) 3C, V/3
(b) C/3 , 3V
(c) 3C, 3V
(d) C/3 , V/3

B

Question. Some charge is being given to a conductor. Then its potential is
(a) maximum at surface
(b) maximum at centre
(c) remain same throughout the conductor
(d) maximum somewhere between surface and centre.

C

Question. Two metallic spheres of radii 1 cm and 2 cm are given charges 10–2 C and 5 × 10–2 C respectively.
If they are connected by a conducting wire, the final charge on the smaller sphere is
(a) 3 × 10–2 C
(b) 4 × 10–2 C
(c) 1 × 10–2 C
(d) 2 × 10–2 C

D

Question. The electrostatic force between the metal plates of an isolated parallel plate capacitor C having a charge Q and area A, is
(a) independent of the distance between the plates
(b) linearly proportional to the distance between the plates
(c) proportional to the square root of the distance between the plates
(d) inversely proportional to the distance between the plates.

A

Question. A parallel plate air capacitor has capacity C, distance of separation between plates is d and potential difference V is applied between the plates. Force of attraction between the plates of the parallel plate air capacitor is
(a) CV2/d
(b) C2V2/2d2
(c) C2V2/d
(d) CV2/d

D

Question. 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

A

Question. The capacitance of a parallel plate capacitor with air as medium is 6 mF. With the introduction of a dielectric medium, the capacitance becomes 30 mF. The permittivity of the medium is (e0 = 8.85 × 10–12 C2 N–1 m–2)
(a) 0.44 × 10–13 C2 N–1 m–2
(b) 1.77 × 10–12 C2 N–1 m–2
(c) 0.44 × 10–10 C2 N–1 m–2
(d) 5.00  C2 N–1 m–2

C

Question. Three concentric spherical shells have radii a, b and c (a < b < c) and have surface charge densities s, –s and s respectively. If VA, VB and VC denote the potentials of the three shells, then, for c = a + b, we have
(a) VC = VB ≠ VA
(b) VC ≠ VB ≠ VA
(c) VC = VB = VA
(d) VC = VA ≠ VB

D

Question. A hollow metallic sphere of radius 10 cm is charged such that potential of its surface is 80 V. The potential at the centre of the sphere would be
(a) 80 V
(b) 800 V
(c) zero
(d) 8 V

A

Question. Two parallel metal plates having charges +Q and –Q face each other at a certain distance between them.
If the plates are now dipped in kerosene oil tank, the electric field between the plates will
(a) become zero
(b) increase
(c) decrease
(d) remain same

C

Question. Three capacitors each of capacity 4 mF are to be connected in such a way that the effective capacitance is 6 mF. This can be done by
(a) connecting all of them in series
(b) connecting them in parallel
(c) connecting two in series and one in parallel
(d) connecting two in parallel and one in series.

C

Question. A series combination of n1 capacitors, each of value C1, is charged by a source of potential difference 4V.
When another parallel combination of n2 capacitors, each of value C2, is charged by a source of potential difference V, it has the same (total) energy stored in it, as the first combination has. The value of C2, in terms of C1, is then
(a) 2C1/n1n2
(b) 16 n2/n1 . C1
(c) 2n2/n1 . C1
(d) 16C1. n2/n1

D

Question. The energy stored in a capacitor of capacity C and potential V is given by
(a) CV/2
(b) C2/V2
(c) C2V/2
(d) CV2

D

Question. The four capacitors, each of 25 μ F are connected as shown in fig. The dc voltmeter reads 200 V. The charge on each plate of capacitor is

(a) ± 2´10-3C
(b) ± 5´10-3C
(c) ± 2´10-2C
(d) ± 5´10-2C

B

Question. An air capacitor of capacity C = 10 μF is connected to a constant voltage battery of 12 volt. Now the space between the plates is filled with a liquid of dielectric constant 5. The (additional) charge that flows now from battery to the capacitor is
(a) 120 μ C
(b) 600 μ C
(c) 480 μ C
(d) 24 μ C

C

Question. Capacitance (in F) of a spherical conductor with radius 1 m is
(a) 1.1 × 10–10
(b) 106
(c) 9 × 10–9
(d) 10–3

A

Question. Two equally charged spheres of radii a and b are connected together. What will be the ratio of electric field intensity on their surfaces?
(a) a/b
(a) a2/b2
(a) b/a
(a) b2/a2

C

Question. In a hollow spherical shell, potential (V) changes with respect to distance (s) from centre as

B

Question. Two metal pieces having a potential difference of 800 V are 0.02 m apart horizontally. A particle of mass 1.96 × 10–15 kg is suspended in equilibrium between the plates. If e is the elementary charge, then charge on the particle is
(a) 8
(b) 6
(c) 0.1
(d) 3

D

Question. The capacity of a parallel plate condenser is 10 μF, when the distance between its plates is 8 cm. If the distance between the plates is reduced to 4 cm, then the capacity of this parallel plate condenser will be
(a) 5 μF
(b) 10 μF
(c) 20 μF
(d) 40 μF

C

Question. The plates of a parallel plate capacitor have an area of 90 cm2 each and are separated by 2.5 mm. The capacitor is charged by a 400 volt supply. How much electrostatic energy is stored by the capacitor?
(a) 2.55 × 10–6 J
(b) 1.55 × 10–6 J
(c) 8.15 × 10–6 J
(d) 5.5 × 10–6 J

A

Question. Two capacitors, C1 = 2μF and C2 = 8 mF are connected in series across a 300 V source. Then
(a) the charge on each capacitor is 4.8×10–4 C
(b) the potential difference across C1 is 60 V
(c) the potential difference across C2 is 240 V
(d) the energy stroed in the system is 5.2 × 10–2 J

A

Question. Two capacitors C1 and C2 = 2C1 are connected in a circuit with a switch between them as shown in the figure. Initially the switch is open and C1 holds charge Q. The switch is closed. At steady state, the charge on each capacitor will be

B

Question. From a supply of identical capacitors rated 8 mF, 250V, the minimum number of capacitors required to form a composite 16 μF, 1000V is
(a) 2
(b) 4
(c) 16
(d) 32

D

Question. The capacitor, whose capacitance is 6, 6 and 3μF respectively are connected in series with 20 volt line. Find the charge on 3μF.
(a) 30 μc
(b) 60 μF
(c) 15 μF
(d) 90 μF

A

Assertion and Reasoning Based Questions :

a : If Assertion and reason are both true and reason is the correct explanation for Assertion.
b : If Assertion and reason are both true but reason is not the correct explanation for Assertion.
c : If Assertion is true but reason is false.
d : If Assertion is false but Reason is true.

Question. Assertion (A): A parallel plate capacitor is charged by a battery. While the battery remains connected, a dielectric slab of dielectric constant K is introduced between the plates of the capacitor. Energy stored by the capacitor becomes K times.
Reason (R) : Surface charge density of the capacitor plates remain constant.

C

Question. Assertion (A): Work done by electrostatic force in bringing a negative test charge (-q) from infinity to point P is Negative in the given situation.

Reason (R) : Work done by a force is a scalar quantity.

D

Question. Assertion (A): The expression of potential energy, U = KQ1 Q2 /r is unaltered whatever way the charges are brought to the specified location.
Reason (R) : Electrostatic force is a conservative force.

A

Question. Assertion (A): On increasing the charge on the plates of a capacitor, its capacitance also increases.
Reason (R): C = Q/V

D

Question. Assertion (A) : A positively charged particle is released from rest in a uniform electric field region. The electrostatic PE of the SYSTEM OF CHARGES will decrease.
Reason (R) : KE of the positive charge increases due to electrostatic force.

A

Question. Assertion (A): Electric potential at any point on the equator of a dipole is zero whereas the electric field at the same point is non zero.
Reason (R) : Electric potential is a vector quantity.

C

Question. Assertion (A): Charge on all the capacitors joined in series is same.
Reason (R) : Charge stored by a capacitor is inversely proportional to the potential difference across its plates.