Electrostatic Potential and Capacitance: JEE Main Previous Year Questions (2021-2026)

 Page 1


JEE Main Previous Year Questions (2021-2026): 
Electrostatic Potential and Capacitance 
 
(January 2026) 
 
Q1: Identify the correct statements: 
A. Effective capacitance of a series combination of capacitors is always smaller than the 
smallest capacitance of the capacitor in the combination. 
B. When a dielectric medium is placed between the charged plates of a capacitor, 
displacement of charges cannot occur due to insulation property of dielectric. 
C. Increasing of area of capacitor plate or decreasing of thickness of dielectric is an 
alternate method to increase the capacitance. 
D. For a point charge, concentric spherical shells centered at the location of the charge 
are equipotential surfaces. 
Choose the correct answer from the options given below : 
(a) A, C and D Only 
(b) A, B and C Only 
(c) B and D Only 
(d) C and D Only 
Ans: (a) 
Sol: 
In a series combination, the effective capacitance (C
eff
) is given by: 
 
Mathematically, the sum of reciprocals always results in a total value that is less than any 
individual component. Hence, statement (A) is correct.  
While dielectrics are insulators and do not allow the flow of current (conduction), they absolutely 
allow the displacement of charges. Under an external electric field, the molecules in a dielectric 
polarize, i.e., their positive and negative charges shift slightly in opposite directions. This is 
known as dielectric polarization. 
Page 2


JEE Main Previous Year Questions (2021-2026): 
Electrostatic Potential and Capacitance 
 
(January 2026) 
 
Q1: Identify the correct statements: 
A. Effective capacitance of a series combination of capacitors is always smaller than the 
smallest capacitance of the capacitor in the combination. 
B. When a dielectric medium is placed between the charged plates of a capacitor, 
displacement of charges cannot occur due to insulation property of dielectric. 
C. Increasing of area of capacitor plate or decreasing of thickness of dielectric is an 
alternate method to increase the capacitance. 
D. For a point charge, concentric spherical shells centered at the location of the charge 
are equipotential surfaces. 
Choose the correct answer from the options given below : 
(a) A, C and D Only 
(b) A, B and C Only 
(c) B and D Only 
(d) C and D Only 
Ans: (a) 
Sol: 
In a series combination, the effective capacitance (C
eff
) is given by: 
 
Mathematically, the sum of reciprocals always results in a total value that is less than any 
individual component. Hence, statement (A) is correct.  
While dielectrics are insulators and do not allow the flow of current (conduction), they absolutely 
allow the displacement of charges. Under an external electric field, the molecules in a dielectric 
polarize, i.e., their positive and negative charges shift slightly in opposite directions. This is 
known as dielectric polarization. 
 
Hence, the statement (B) is incorrect. 
The capacitance (C) of a parallel plate capacitor is given by: 
 
Where A is the area and d is the distance (thickness of dielectric). 
If A increases, C increases  
If d decreases, C increases 
Hence, the statement (C) is correct.  
The potential (V) due to a point charge is V = kq/r . 
This means the potential depends only on the distance (r) from the charge.  
For a fixed r , the potential is constant. All points at a constant distance r from a center form a 
spherical shell. Therefore, these concentric shells are equipotential surfaces.  
Hence, the statement (D) is correct.  
Statements A, C, and D are true, while statement B is false. Hence, the correct option is (A). 
 
 
Q2: Three parallel plate capacitors each with area A and separation d are filled with two 
dielectric (k
1
 and k
2
) in the following fashion. Which of the following is true? (k
1
 > k
2
) 
Page 3


JEE Main Previous Year Questions (2021-2026): 
Electrostatic Potential and Capacitance 
 
(January 2026) 
 
Q1: Identify the correct statements: 
A. Effective capacitance of a series combination of capacitors is always smaller than the 
smallest capacitance of the capacitor in the combination. 
B. When a dielectric medium is placed between the charged plates of a capacitor, 
displacement of charges cannot occur due to insulation property of dielectric. 
C. Increasing of area of capacitor plate or decreasing of thickness of dielectric is an 
alternate method to increase the capacitance. 
D. For a point charge, concentric spherical shells centered at the location of the charge 
are equipotential surfaces. 
Choose the correct answer from the options given below : 
(a) A, C and D Only 
(b) A, B and C Only 
(c) B and D Only 
(d) C and D Only 
Ans: (a) 
Sol: 
In a series combination, the effective capacitance (C
eff
) is given by: 
 
Mathematically, the sum of reciprocals always results in a total value that is less than any 
individual component. Hence, statement (A) is correct.  
While dielectrics are insulators and do not allow the flow of current (conduction), they absolutely 
allow the displacement of charges. Under an external electric field, the molecules in a dielectric 
polarize, i.e., their positive and negative charges shift slightly in opposite directions. This is 
known as dielectric polarization. 
 
Hence, the statement (B) is incorrect. 
The capacitance (C) of a parallel plate capacitor is given by: 
 
Where A is the area and d is the distance (thickness of dielectric). 
If A increases, C increases  
If d decreases, C increases 
Hence, the statement (C) is correct.  
The potential (V) due to a point charge is V = kq/r . 
This means the potential depends only on the distance (r) from the charge.  
For a fixed r , the potential is constant. All points at a constant distance r from a center form a 
spherical shell. Therefore, these concentric shells are equipotential surfaces.  
Hence, the statement (D) is correct.  
Statements A, C, and D are true, while statement B is false. Hence, the correct option is (A). 
 
 
Q2: Three parallel plate capacitors each with area A and separation d are filled with two 
dielectric (k
1
 and k
2
) in the following fashion. Which of the following is true? (k
1
 > k
2
) 
 
 
(a) C
C
 > C
B
 > C
A 
(b) C
B
 > C
C
 > C
A 
(c) C
A
 > C
C
 > C
B 
(d) C
C
 > C
A
 > C
B 
Ans: (c) 
Sol: 
The capacitance of a parallel plate capacitor is , where k is the dielectric 
constant of the material, A is the area of the plate and d is the separation between the plates.  
When capacitors are in parallel then the equivalent capacitance is given as  
 
When capacitors are in series then the equivalent capacitance is given as 
 
For Capacitor (A) 
Page 4


JEE Main Previous Year Questions (2021-2026): 
Electrostatic Potential and Capacitance 
 
(January 2026) 
 
Q1: Identify the correct statements: 
A. Effective capacitance of a series combination of capacitors is always smaller than the 
smallest capacitance of the capacitor in the combination. 
B. When a dielectric medium is placed between the charged plates of a capacitor, 
displacement of charges cannot occur due to insulation property of dielectric. 
C. Increasing of area of capacitor plate or decreasing of thickness of dielectric is an 
alternate method to increase the capacitance. 
D. For a point charge, concentric spherical shells centered at the location of the charge 
are equipotential surfaces. 
Choose the correct answer from the options given below : 
(a) A, C and D Only 
(b) A, B and C Only 
(c) B and D Only 
(d) C and D Only 
Ans: (a) 
Sol: 
In a series combination, the effective capacitance (C
eff
) is given by: 
 
Mathematically, the sum of reciprocals always results in a total value that is less than any 
individual component. Hence, statement (A) is correct.  
While dielectrics are insulators and do not allow the flow of current (conduction), they absolutely 
allow the displacement of charges. Under an external electric field, the molecules in a dielectric 
polarize, i.e., their positive and negative charges shift slightly in opposite directions. This is 
known as dielectric polarization. 
 
Hence, the statement (B) is incorrect. 
The capacitance (C) of a parallel plate capacitor is given by: 
 
Where A is the area and d is the distance (thickness of dielectric). 
If A increases, C increases  
If d decreases, C increases 
Hence, the statement (C) is correct.  
The potential (V) due to a point charge is V = kq/r . 
This means the potential depends only on the distance (r) from the charge.  
For a fixed r , the potential is constant. All points at a constant distance r from a center form a 
spherical shell. Therefore, these concentric shells are equipotential surfaces.  
Hence, the statement (D) is correct.  
Statements A, C, and D are true, while statement B is false. Hence, the correct option is (A). 
 
 
Q2: Three parallel plate capacitors each with area A and separation d are filled with two 
dielectric (k
1
 and k
2
) in the following fashion. Which of the following is true? (k
1
 > k
2
) 
 
 
(a) C
C
 > C
B
 > C
A 
(b) C
B
 > C
C
 > C
A 
(c) C
A
 > C
C
 > C
B 
(d) C
C
 > C
A
 > C
B 
Ans: (c) 
Sol: 
The capacitance of a parallel plate capacitor is , where k is the dielectric 
constant of the material, A is the area of the plate and d is the separation between the plates.  
When capacitors are in parallel then the equivalent capacitance is given as  
 
When capacitors are in series then the equivalent capacitance is given as 
 
For Capacitor (A) 
 
The capacitance,  
The capacitance,  
The capacitance,  
C
A2
 and C
A3
 are in parallel, 
 
Now, C
A1
 and C
A(2,3)
 are in series, so the equivalent capacitance of capacitor A is 
 
Page 5


JEE Main Previous Year Questions (2021-2026): 
Electrostatic Potential and Capacitance 
 
(January 2026) 
 
Q1: Identify the correct statements: 
A. Effective capacitance of a series combination of capacitors is always smaller than the 
smallest capacitance of the capacitor in the combination. 
B. When a dielectric medium is placed between the charged plates of a capacitor, 
displacement of charges cannot occur due to insulation property of dielectric. 
C. Increasing of area of capacitor plate or decreasing of thickness of dielectric is an 
alternate method to increase the capacitance. 
D. For a point charge, concentric spherical shells centered at the location of the charge 
are equipotential surfaces. 
Choose the correct answer from the options given below : 
(a) A, C and D Only 
(b) A, B and C Only 
(c) B and D Only 
(d) C and D Only 
Ans: (a) 
Sol: 
In a series combination, the effective capacitance (C
eff
) is given by: 
 
Mathematically, the sum of reciprocals always results in a total value that is less than any 
individual component. Hence, statement (A) is correct.  
While dielectrics are insulators and do not allow the flow of current (conduction), they absolutely 
allow the displacement of charges. Under an external electric field, the molecules in a dielectric 
polarize, i.e., their positive and negative charges shift slightly in opposite directions. This is 
known as dielectric polarization. 
 
Hence, the statement (B) is incorrect. 
The capacitance (C) of a parallel plate capacitor is given by: 
 
Where A is the area and d is the distance (thickness of dielectric). 
If A increases, C increases  
If d decreases, C increases 
Hence, the statement (C) is correct.  
The potential (V) due to a point charge is V = kq/r . 
This means the potential depends only on the distance (r) from the charge.  
For a fixed r , the potential is constant. All points at a constant distance r from a center form a 
spherical shell. Therefore, these concentric shells are equipotential surfaces.  
Hence, the statement (D) is correct.  
Statements A, C, and D are true, while statement B is false. Hence, the correct option is (A). 
 
 
Q2: Three parallel plate capacitors each with area A and separation d are filled with two 
dielectric (k
1
 and k
2
) in the following fashion. Which of the following is true? (k
1
 > k
2
) 
 
 
(a) C
C
 > C
B
 > C
A 
(b) C
B
 > C
C
 > C
A 
(c) C
A
 > C
C
 > C
B 
(d) C
C
 > C
A
 > C
B 
Ans: (c) 
Sol: 
The capacitance of a parallel plate capacitor is , where k is the dielectric 
constant of the material, A is the area of the plate and d is the separation between the plates.  
When capacitors are in parallel then the equivalent capacitance is given as  
 
When capacitors are in series then the equivalent capacitance is given as 
 
For Capacitor (A) 
 
The capacitance,  
The capacitance,  
The capacitance,  
C
A2
 and C
A3
 are in parallel, 
 
Now, C
A1
 and C
A(2,3)
 are in series, so the equivalent capacitance of capacitor A is 
 
For Capacitor (B) 
 
 
Now, C
B1
 and C
B(2,3)
 are in series, so the equivalent capacitance of capacitor B is