Electrostatics

Easy Recall (3)Direct Application (3)Calculation (2)

Capacitors Series Parallel

Easy Recall (3)Direct Application (3)Calculation (2)

Coulomb's Law

Easy Recall (3)Direct Application (3)Calculation (2)

Electric Charges Conservation

8 MCQs1 PYQsWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Electric Dipole

8 MCQs2 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Electric Field Lines

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Electric Field Point Charge

Easy Recall (3)Direct Application (3)Calculation (2)

Electric Flux

Easy Recall (3)Direct Application (3)Calculation (2)

Electric Potential

8 MCQs5 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Electrical Potential Energy Two Charges

Easy Recall (3)Direct Application (3)Calculation (2)

Energy in Capacitor

8 MCQs2 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Equipotential Surfaces

8 MCQs1 PYQsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Field Long Wire Gauss

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Field Plane Sheet Gauss

Easy Recall (3)Direct Application (3)Calculation (2)

Field Spherical Shell Gauss

8 MCQs4 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Gauss's Law

8 MCQs1 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Parallel Plate Capacitor

8 MCQs3 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Potential Difference

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Superposition Principle

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Torque Dipole

8 MCQs2 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (2)

Past-paper questions from this unit

21 questions from NEET 2020, 2021, 2022, 2023, 2024, 2025, 2026. Answers verified against NTA official keys.

By year in our set: 2020 (4) · 2021 (1) · 2022 (3) · 2023 (3) · 2024 (4) · 2025 (2) · 2026 (4)

Lesson: Energy in Capacitor

NEET 2026

Three identical capacitors P, Q and S, each of the capacitance C, are connected to a battery of voltage V, as shown in the figure. If the energy stored in the capacitor P and total energy stored in the system are U_P and U_T, respectively, then the ratio U_P/U_T is :

12/3

21/3

31/2

41/6

NTA Answer: Option 4(final)

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A unit positive point charge is taken slowly through an infinitesimally thin tube that is inside a charged dielectric sphere of radius R, having uniform positive charge density ρ, as shown in the figure. The initial and final positions of the charge are marked by A and B at distances 2R and 3R respectively, from the centre of the sphere. In this process, the magnitude of the total work done on the point charge is ρR²/(nε₀). The value of n is : (ε₀ is the permittivity of vacuum)

NEET 2026

418

NTA Answer: Option 4(final)

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A point charge Q is placed inside a cavity within a solid isolated conducting sphere. Consider points A, B and C as shown in the figure, where the magnitudes of the electric fields are E_A, E_B and E_C, respectively. The points B and C are at the same distance from the center of the solid sphere. The correct option is :

NEET 2026

1E_A = 0, E_B = E_C

2E_A ≠ 0, E_B = E_C

3E_A = 0, E_B > E_C

4E_A ≠ 0, E_B < E_C

NTA Answer: Option 2(final)

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Lesson: Electric Potential

NEET 2026

Consider a fixed uniformly charged insulating sphere with radius R and total charge +Q. A point charge −q (q << Q) with mass m is released from rest at a distance of 3R from the centre of the charged sphere. When the point charge reaches the surface of the sphere, its speed is : (ε₀ is the permittivity of vacuum, neglect gravitational forces)

1√(3Qq/(4πε₀mR))

2√(2Qq/(3πε₀mR))

3√(Qq/(3πε₀mR))

4√(Qq/(4πε₀mR))

NTA Answer: Option 3(final)

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Lesson: Torque Dipole

NEET 2025

An electric dipole with dipole moment 5 × 10⁻⁶ C m is aligned with the direction of a uniform electric field of magnitude 4 × 10⁵ N/C. The dipole is then rotated through an angle of 60° with respect to the electric field. The change in the potential energy of the dipole is:

11.5 J

20.8 J

31.0 J

41.2 J

NTA Answer: Option 3(final)

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The plates of a parallel plate capacitor are separated by d. Two slabs of different dielectric constant K₁ and K₂ with thickness (3/8)d and d/2, respectively are inserted in the capacitor. Due to this, the capacitance becomes two times larger than when there is nothing between the plates. If K₁ = 1.25 K₂, the value of K₁ is:

NEET 2025

11.33

22.66

32.33

41.60

NTA Answer: Option 2(final)

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Lesson: Electric Charges Conservation

NEET 2024Revised key

Given below are two statements: Statement I: Atoms are electrically neutral as they contain equal number of positive and negative charges. Statement II: Atoms of each element are stable and emit their characteristic spectrum. In the light of the above statements, choose the most appropriate answer from the options given below.

1Both Statement I and Statement II are correct

2Both Statement I and Statement II are incorrect

3Statement I is correct but Statement II is incorrect

4Statement I is incorrect but Statement II is correct

NTA Answer: Option 3(revised_final)

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A thin spherical shell is charged by some source. The potential difference between the two points C and P (in V) shown in the figure is: (Take 1/(4πε₀) = 9 × 10⁹ SI units)

NEET 2024Revised key

13 × 10⁵

21 × 10⁵

30.5 × 10⁵

4Zero

NTA Answer: Option 4(revised_final)

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Lesson: Electric Potential

NEET 2024Revised key

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: The potential (V) at any axial point, at 2 m distance (r) from the centre of the dipole of dipole moment vector P⃗ of magnitude, 4 × 10⁻⁶ C m, is ± 9 × 10³ V. (Take 1/(4πε₀) = 9 × 10⁹ SI units) Reason R: V = ± 2P/(4πε₀r²), where r is the distance of any axial point, situated at 2 m from the centre of the dipole. In the light of the above statements, choose the correct answer from the options given below:

1Both A and R are true and R is the correct explanation of A.

2Both A and R are true and R is NOT the correct explanation of A.

3A is true but R is false.

4A is false but R is true.

NTA Answer: Option 3(revised_final)

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If the plates of a parallel plate capacitor connected to a battery are moved close to each other, then A. the charge stored in it, increases. B. the energy stored in it, decreases. C. its capacitance increases. D. the ratio of charge to its potential remains the same. E. the product of charge and voltage increases. Choose the most appropriate answer from the options given below:

NEET 2024Revised key

1A, B and E only

2A, C and E only

3B, D and E only

4A, B and C only

NTA Answer: Option 2(revised_final)

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Lesson: Gauss's Law

NEET 2023

If ∮ₛ E⃗ · dS⃗ = 0 over a surface, then

1The magnitude of electric field on the surface is constant

2All the charges must necessarily be inside the surface

3The electric field inside the surface is necessarily uniform

4The number of flux lines entering the surface must be equal to the number of flux lines leaving it

NTA Answer: Option 4(final)

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Lesson: Torque Dipole

NEET 2023

An electric dipole is placed at an angle of 30° with an electric field of intensity 2 × 10⁵ N C⁻¹. It experiences a torque equal to 4 N m. Calculate the magnitude of charge on the dipole, if the dipole length is 2 cm.

16 mC

24 mC

32 mC

48 mC

NTA Answer: Option 3(final)

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Lesson: Electric Dipole

NEET 2023

An electric dipole is placed as shown in the figure. The electric potential (in 10² V) at point P due to the dipole is (∈₀ = permittivity of free space and 1/(4π∈₀) = K)

1(5/8)qK

2(8/5)qK

3(8/3)qK

4(3/8)qK

NTA Answer: Option 4(final)

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Lesson: Electric Potential

NEET 2022

Two hollow conducting spheres of radii R 1 and R 2 (R 1 >> R 2 ) have equal charges. The potential would be

1Dependent on the material property of the sphere

2More on bigger sphere

3More on smaller sphere

4Equal on both the spheres

NTA Answer: Option 3(final)

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Lesson: Equipotential Surfaces

NEET 2022

The angle between the electric lines of force and the equipotential surface is

1180°

20°

345°

490°

NTA Answer: Option 4(final)

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Lesson: Energy in Capacitor

NEET 2022

A capacitor of capacitance C = 900 pF is charged fully by 100 V battery B as shown in figure (a). Then it is disconnected from the battery and connected to another uncharged capacitor of capacitance C = 900 pF as shown in figure (b). The electrostatic energy stored by the system (b) is

11.5 × 10⁻⁶ J

24.5 × 10⁻⁶ J

33.25 × 10⁻⁶ J

42.25 × 10⁻⁶ J

NTA Answer: Option 4(final)

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Lesson: Electric Potential

NEET 2021

Twenty seven drops of same size are charged at 200 V each. They combine to form a bigger drop. Calculate the potential of the bigger drop.

11980 V

2660 V

31320 V

41520 V

NTA Answer: Option 1(final)

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Lesson: Electric Dipole

NEET 2020

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 N m²/C²)

1zero

250 V

3200 V

4400 V

NTA Answer: Option 3(final)

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Lesson: Electric Potential

NEET 2020

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 :

15 N/C

2zero

30.5 N/C

41 N/C

NTA Answer: Option 2(final)

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A spherical conductor of radius 10 cm has a charge of 3.2 × 10⁻⁷ C distributed uniformly. What is the magnitude of electric field at a point 15 cm from the centre of the sphere ? (1/(4πε₀) = 9 × 10⁹ N m²/C²)

NEET 2020

11.28 × 10⁷ N/C

21.28 × 10⁴ N/C

31.28 × 10⁵ N/C

41.28 × 10⁶ N/C

NTA Answer: Option 3(final)

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The capacitance of a parallel plate capacitor with air as medium is 6 µF. With the introduction of a dielectric medium, the capacitance becomes 30 µF. The permittivity of the medium is : (e0=8.85×10⁻¹² C² N⁻¹ m⁻²)

NEET 2020

15.00 C² N⁻¹ m⁻²

20.44×10⁻¹³ C² N⁻¹ m⁻²

31.77×10⁻¹² C² N⁻¹ m⁻²

40.44×10⁻¹⁰ C² N⁻¹ m⁻²

NTA Answer: Option 4(final)

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Exam traps and common mistakes in this unit

Trap

Capacitor series-parallel formula swap

Category: Similar Terms

Student uses series formula for parallel circuit (or vice versa). Series capacitors: 1/C reciprocals add; parallel: C add directly. Note: opposite of resistor rules.

When it triggers

Capacitor combination problem.

How to avoid

Capacitors in SERIES → reciprocals add (like resistors in parallel). Capacitors in PARALLEL → values add (like resistors in series). Counter-intuitive vs resistor rules — memorise carefully.

Mistake

Uses series formula for parallel capacitors (or vice versa).

Root cause: formula misuse

Correction

OPPOSITE of resistor rules. Capacitors in series → reciprocals add (1/C_eq = Σ1/C_i). Capacitors in parallel → values add (C_eq = ΣC_i). Counter-intuitive vs resistors; memorise carefully.

Mistake

Computes non-zero field inside a charged spherical shell.

Root cause: concept gap

Correction

Gauss's law: enclosed charge inside the shell is zero (charge is all on outside surface), so E = 0 inside. Outside: behaves like point charge.

Formulas in this unit

Lesson: Capacitors Capacitance

Parallel plate capacitor

C = \frac{ε _{r} ε _{0} A}{d}

Capacitance of parallel-plate capacitor. eps_r = 1 for vacuum/air.

Symbol	Quantity	SI Unit
C	capacitance	F
A	plate area	m^2
d	plate separation	m
eps_r	relative permittivity	-

Valid when

Plate separation << plate dimensions (uniform field)
Uniform dielectric

Capacitors series and parallel

\frac{1}{C _{e q}} = \sum \frac{1}{C _{i}}; C_{e q} = \sum C_{i}

Series: same Q on each, voltages add. Parallel: same V across each, charges add.

Symbol	Quantity	SI Unit
C_eq	equivalent capacitance	F
C_i	individual	F

Valid when

Series: same charge through chain
Parallel: same voltage across all

Lesson: Coulomb's Law

Coulomb's law

F = \frac{1}{4 π ε _{0}} \frac{q _{1} q _{2}}{r ^{2}}

Force between two point charges in vacuum. 1/(4*pi*eps0) ~ 9e9 N*m^2/C^2.

Symbol	Quantity	SI Unit
F	force	N
q1,q2	charges	C
r	separation	m
eps0	permittivity 8.85e-12	F/m

Valid when

Point charges (or spherically symmetric)
r > body sizes

Lesson: Electric Dipole

Electric field of dipole — axial

E_{axial} = \frac{2 p}{4 π ε _{0} r ^{3}}

Field on dipole axis at distance r >> dipole size; directed along p.

Symbol	Quantity	SI Unit
p	dipole moment	C*m
r	distance from centre	m

Valid when

r >> 2a (dipole size)
Along axis

Lesson: Electric Field Point Charge

Electric field of point charge

E = \frac{1}{4 π ε _{0}} \frac{q}{r ^{2}}

Field magnitude from point charge q at distance r, directed radially.

Symbol	Quantity	SI Unit
E	electric field	N/C or V/m
q	point charge	C
r	distance	m

Valid when

Point or spherically symmetric source
r > source body radius

Lesson: Electric Potential

Electric potential of point charge

V = \frac{q}{4 π ε _{0} r}

Scalar potential at distance r from point charge q, with V→0 at infinity.

Symbol	Quantity	SI Unit
V	potential	V
q	point charge	C
r	distance	m

Valid when

Reference V=0 at infinity

Lesson: Energy in Capacitor

Energy stored in capacitor

U = \frac{1}{2} C V^{2} = \frac{Q ^{2}}{2 C}

Energy stored as work to charge the capacitor.

Symbol	Quantity	SI Unit
C	capacitance	F
V	voltage	V
Q	charge	C

Valid when

Linear capacitor
Static charging or quasi-static

Lesson: Field Long Wire Gauss

Field of long line charge (Gauss)

E = \frac{λ}{2 π ε _{0} r}

Radial field at perpendicular distance r from infinite line of linear charge density lambda.

Symbol	Quantity	SI Unit
E	field	V/m
lambda	linear charge density	C/m
r	perp distance	m

Valid when

Infinite line (or much longer than r)
Uniform charge density

Lesson: Field Plane Sheet Gauss

Field of charged plane sheet

E = \frac{σ}{2 ε _{0}}

Uniform field perpendicular to a non-conducting infinite plane sheet of surface charge density sigma. Independent of distance.

Symbol	Quantity	SI Unit
sigma	surface charge density	C/m^2
eps0	permittivity	F/m

Valid when

Infinite plane sheet
Non-conducting (otherwise sigma is split between surfaces)

Field of charged spherical shell

E_{out} = \frac{Q}{4 π ε _{0} r ^{2}}; E_{in} = 0

Spherical shell behaves like point charge outside; field is zero inside.

Symbol	Quantity	SI Unit
Q	total charge	C
R	shell radius	m
r	distance from centre	m

Valid when

Spherically symmetric charge distribution
Static

Lesson: Gauss's Law

Gauss's law

\oint E \cdot d A = \frac{Q _{enc}}{ε _{0}}

Total electric flux through closed surface equals enclosed charge over permittivity.

Symbol	Quantity	SI Unit
Phi_E	total flux	V*m
Q_enc	enclosed charge	C

Valid when

Closed surface
All sources accounted for

NEET question patterns in this unit

Combination of capacitors. Series: 1/C = sum(1/C_i); parallel: C = sum(C_i).

Multi StepEasy

Common distractors

swaps series parallel formulas

Uses series formula for parallel circuit

Lesson: Coulomb's Law

Force between two point charges; given q1, q2, r, find F.

Direct ApplicationEasy

Common distractors

forgets 1 over 4pi eps0

Uses naive q1q2/r^2 without constant

Lesson: Electric Dipole

Dipole in uniform E field: torque tau = pE sin(theta); compute force, torque, or PE.

Multi StepMedium

Common distractors

uses r cubed formula for far field when near charges

Wrong formula regime

Lesson: Electric Potential

Total potential at a point = scalar sum of potentials from each charge.

Multi StepMedium

Common distractors

uses vector sum

Adds V as vector instead of scalar

Charged spherical shell: field inside zero, outside as point charge. Apply Gauss's law to find E at given r.

InterpretationMedium

Common distractors

treats shell like solid sphere

Includes interior charge contribution where there is none