JEE Main · Physics · Electrostatic Potential and Capacitance
Dielectrics: JEE Main previous year questions
25 questions in the 108 JEE Main shifts Lumi analysed, in 6 of 8 years. Pattern: Asked most years. 11 came in 2024–26. Here is how it is asked and which ideas come back.
- Questions
- 25
- in 25 of 108 shifts
- Years asked
- 6/8
- last asked 2026
- Weighted estimate
- 0.3
- model; history: 0.2 a shift on average, typically 0.0–0.2
Key findings
- 01
Asked in 6 of 8 years with analysed shifts and in 25 of 108 shifts: 25 questions, #124 of 196 topics.
- 02
40% of its questions since 2020 tested an idea no earlier year had asked; 10 repeated an idea from the year before.
- 03
The most repeated idea is Partial and Multiple Slabs, asked 10 times in 10 shifts (2021, 2022, 2023, 2024, 2025, 2026), most often as “capacitance change with partial dielectric slab”.
- 04
JEE Main has asked 9 of the 54 ideas in this topic; 40 have never been asked, directly or inside another question.
- 05
Mostly asked as numerical value (48%); 48% need a numerical answer, 36% are easy and 12% hard. It went up from 0.1 to 0.3 questions a shift since 2024.
- 06
The skill tested most is calculation (36%), then multi-step (36%).
Questions a shift, year by year
Out of the 25 Physics questions in a shift. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift.
Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 6 in 24 shifts · 2022: 7 in 24 shifts · 2023: 1 in 12 shifts · 2024: 4 in 18 shifts · 2025: 5 in 8 shifts · 2026: 2 in 9 shifts.
- Up to 2023
- 0.1
- a shift, of 25
- Since 2024
- 0.3
- 0.2
- Usual gap
- 1.0 yrs
- between years asking it
- Shifts with it
- 25/108
- 23% of analysed shifts
How it is asked
Difficulty, format and skill
Across all 25 questions on Dielectrics since 2017.
Difficulty
QUESTIONS- Easy9 · 36%
- Medium13 · 52%
- Hard3 · 12%
Format
SHARE- Numerical value · 12 Q48%
- Single correct · 9 Q36%
- Diagram based · 2 Q8%
- Assertion–reason · 2 Q8%
Skill tested
SHARE- Calculation · 9 Q36%
- Multi-step · 9 Q36%
- Application · 4 Q16%
- Conceptual · 3 Q12%
Repeats
New idea, or one asked before?
Each column is a year. Blue questions tested an idea no earlier year had asked; navy ones went back to an idea from an earlier year. 2017 is the first year, so everything in it counts as new. Heights are question counts, and Lumi analysed 1 to 24 shifts a year, so compare the split inside a column rather than heights across years.
- Idea asked for the first time
- Idea asked in an earlier year
Coverage of the topic
JEE Main has asked 9 of the 54 ideas in this topic. 40 have never been asked yet.
- Asked directly9 · 17%
- Touched inside another question5 · 9%
- Never asked40 · 74%
Ideas come from Lumi’s JEE syllabus map. A never-asked idea is not a safe skip: across all of JEE Main, 22% of questions since 2024 tested an idea no earlier year had asked.
Drill down
Chapter, idea, question
Every idea JEE Main tested in this topic, with its eight years. Open one to read the questions.
8 ideas inside
Squares are the 8 years with analysed shifts, 2017 to 2026. A number is the questions that year when there is more than one; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker. Share is of the level above.
Ideas
Every idea inside this topic
9 different ideas were tested; 6 came more than once.
capacitance change with partial dielectric slab
Numerical value · 10 shifts · 5 numericaldielectric constant from charge change
Numerical value · 3 shifts · 2 numericalenergy change on inserting dielectric after disconnecting battery
Numerical value · 3 shifts · 3 numericaleffective capacitance with dielectric in one capacitor
Single correct · 2 shiftsdielectric constant from induced charge
Numerical value · 2 shifts · 1 numericalassertion-reason on dielectrics
Assertion–reason · 2 shiftspermittivity of leaky dielectric
Numerical value · 1 shift · 1 numericalcapacitance ratio for two slab configurations
Diagram based · 1 shiftleakage current of capacitor with resistive dielectric
Single correct · 1 shift
| Idea | Years asked | Times | Shifts | Format | Numerical |
|---|---|---|---|---|---|
| Partial and Multiple Slabscapacitance change with partial dielectric slab | 10 | 10 | Numerical valueCalculation | 5 | |
| Dielectric with Battery Connecteddielectric constant from charge change | 3 | 3 | Numerical valueCalculation | 2 | |
| Dielectric with Battery Disconnectedenergy change on inserting dielectric after disconnecting battery | 3 | 3 | Numerical valueMulti-step | 3 | |
| Capacitance with Full Slabeffective capacitance with dielectric in one capacitor | 2 | 2 | Single correctMulti-step | – | |
| Induced Surface Charge Densitydielectric constant from induced charge | 2 | 2 | Numerical valueApplication | 1 | |
| Polar vs. Non-Polar Dielectricsassertion-reason on dielectrics | 2 | 2 | Assertion–reasonConceptual | – | |
| Leaky Dielectric as an RC Circuitpermittivity of leaky dielectric | 1 | 1 | Numerical valueMulti-step | 1 | |
| Identifying Series vs Parallel Slab Configurationscapacitance ratio for two slab configurations | 1 | 1 | Diagram basedMulti-step | – | |
| Leaky Dielectric and RC Equivalentleakage current of capacitor with resistive dielectric | 1 | 1 | Single correctMulti-step | – |
Times and shifts count every analysed shift. Across JEE Main, 78% of questions since 2024 went back to an idea an earlier year had asked; the rest were new. All repeated ideas
Every question
Dielectrics questions, year by year
The opening words of each question as it appeared in the official paper, with the idea it tested. Open one for its options and the official answer.
JEE Main 20262 questions in 2 shifts
- 2 Apr, Shift 1Q32A parallel plate air capacitor has a capacitance C. When it is half filled as show in figure with a dielectric constant , the…
Idea: Partial and Multiple Slabs
Asked the year beforeEasySingle correct · figure - 8 Apr, Shift 2Q46A parallel plate capacitor is having separation between plates 0.885 mm. It has a capacitance of 1 F when the space between the…
Idea: Leaky Dielectric as an RC Circuit
New ideaHardNumerical value
JEE Main 20255 questions in 5 shifts
- 2 Apr, Shift 2Q41Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Net dipole…
Idea: Polar vs. Non-Polar Dielectrics
EasyAssertion–reason - 3 Apr, Shift 1Q38A parallel plate capacitor is filled equally(half) with two dielectrics of dielectric constants and , as shown in…
Idea: Identifying Series vs Parallel Slab Configurations
New ideaMediumDiagram based · figure - 4 Apr, Shift 2Q35Three parallel plate capacitors , and each of capacitance 5 F are connected as shown in figure. The effective…
Idea: Capacitance with Full Slab
EasySingle correct · figure - 7 Apr, Shift 2Q49A parallel plate capacitor has charge C. A dielectric slab is inserted between the plates and almost fills the space…
Idea: Induced Surface Charge Density
MediumNumerical value - 8 Apr, Shift 2Q49Space between the plates of a parallel plate capacitor of plate area 4 cm and separation of (d) 1.77 mm, is filled with uniform…
Idea: Partial and Multiple Slabs
Asked the year beforeMediumNumerical value · figure
JEE Main 20244 questions in 4 shifts
- 4 Apr, Shift 2Q60A parallel plate capacitor of capacitance 12.5 is charged by a battery connected between its plates to potential difference of 12.0…
Idea: Dielectric with Battery Disconnected
MediumNumerical value - 6 Apr, Shift 2Q52A capacitor of capacitance whose plates are separated by 10 mm through air and each plate has area …
Idea: Partial and Multiple Slabs
Asked the year beforeHardNumerical value · figure - 8 Apr, Shift 2Q40A capacitor has air as dielectric medium and two conducting plates of area and they are cm apart. When a slab of…
Idea: Partial and Multiple Slabs
Asked the year beforeMediumSingle correct - 31 Jan, Shift 1Q55A parallel plate capacitor with plate separation 5 mm is charged up by a battery. It is found that on introducing a dielectric sheet of…
Idea: Dielectric with Battery Connected
MediumNumerical value
JEE Main 20231 question in 1 shift
- 6 Apr, Shift 1Q56A parallel plate capacitor with plate area A and plate separation d is filled with a dielectric material of dielectric constant . The…
Idea: Partial and Multiple Slabs
Asked the year beforeMediumNumerical value · figure
JEE Main 20227 questions in 7 shifts
- 25 Jul, Shift 2Q58Two parallel plate capacitors of capacity C and 3C are connected in parallel combination and charged to a potential difference 18 V. The…
Idea: Dielectric with Battery Disconnected
Asked the year beforeMediumNumerical value - 27 Jul, Shift 2Q56A parallel plate capacitor with width 4 cm, length 8 cm and separation between the plates of 4 mm is connected to a battery of 20 V. A…
Idea: Partial and Multiple Slabs
Asked the year beforeMediumNumerical value - 28 Jul, Shift 1Q40Two capacitors, each having capacitance 40 F are connected in series. The space between one of the capacitors is filled with…
Idea: Capacitance with Full Slab
New ideaMediumSingle correct - 28 Jul, Shift 2Q9A slab of dielectric constant K has the same cross-sectional area as the plates of a parallel plate capacitor and thickness …
Idea: Partial and Multiple Slabs
Asked the year beforeEasySingle correct - 26 Jun, Shift 1Q41Given below two statements : One is labelled as Assertion (A) and other is labelled as Reason (R). Assertion (A) : Non-polar materials do…
Idea: Polar vs. Non-Polar Dielectrics
New ideaEasyAssertion–reason - 29 Jun, Shift 1Q47A parallel plate capacitor filled with a medium of dielectric constant 10, is connected across a battery and is charged. The dielectric…
Idea: Dielectric with Battery Connected
Asked the year beforeEasySingle correct - 30 Jun, Shift 1Q40is the capacitance of a parallel plate capacitor with air as a medium between the plates (as shown in Fig. 1). If half…
Idea: Partial and Multiple Slabs
Asked the year beforeEasySingle correct · figure
JEE Main 20216 questions in 6 shifts
- 26 Aug, Shift 1Q14The material filled between the plates of a parallel plate capacitor has resistivity 200 m. The value of capacitance of the…
Idea: Leaky Dielectric and RC Equivalent
New ideaMediumSingle correct - 26 Aug, Shift 2Q18A parallel-plate capacitor with plate area A has separation d between the plates. Two dielectric slabs of dielectric constant…
Idea: Partial and Multiple Slabs
New ideaMediumDiagram based · figure - 31 Aug, Shift 2Q23A parallel plate capacitor of capacitance 200 F is connected to a battery of 200 V. A dielectric slab of dielectric constant 2 is now…
Idea: Dielectric with Battery Connected
New ideaEasyNumerical value - 25 Jul, Shift 2Q11If is the free charge on the capacitor plates and is the bound charge on the dielectric slab of dielectric constant placed…
Idea: Induced Surface Charge Density
New ideaEasySingle correct - 17 Mar, Shift 1Q25A parallel plate capacitor whose capacitance C is 14 pF is charged by a battery to a potential difference V = 12 V between its plates. The…
Idea: Dielectric with Battery Disconnected
New ideaHardNumerical value - 18 Mar, Shift 1Q29A parallel plate capacitor has plate area 100 m and plate separation of 10 m. The space between the plates is filled up to a thickness…
Idea: Partial and Multiple Slabs
New ideaMediumNumerical value
Questions from the official JEE Main Paper 1 shifts published by NTA (CBSE for 2017). Questions NTA dropped are left out. Topic and idea tags, counts and notes are Lumi’s.