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Saturday, 31 October

JEE Main 2025 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 8 April 2025, Shift 2, Physics Q49

Question 49 of 75 in this shift, Physics question 24 of 25, Section B.

Space between the plates of a parallel plate capacitor of plate area 4 cm2^2 and separation of (d) 1.77 mm, is filled with uniform dielectric materials with dielectric constants (3 and 5) as shown in figure. Another capacitor of capacitance 7.5 pF is connected in parallel with it. The effective capacitance of this combination is __________ pF. (Given ϵ0=8.85×10−12\epsilon_0 = 8.85 \times 10^{-12} F/m)

The figure, in words

Parallel plate capacitor: upper layer (hatched) of dielectric constant k = 5 and thickness d/2; lower layer (dotted) of dielectric constant k = 3 and thickness d/2; leads attached to top and bottom plates.

Official answer

15

NTA final key.

Chapter
Electrostatic Potential and Capacitance
Topic
Dielectrics
Idea tested
Partial and Multiple Slabs

Same idea in other shifts

Asked 10× in all
  1. 2 Apr 2026, Shift 1 · Q32A parallel plate air capacitor has a capacitance C. When it is half filled as show in figure with a dielectric constant K=5K=5, the…EasySingle correctHas a figure
  2. 6 Apr 2024, Shift 2 · Q52A capacitor of 10 μF10\ \mu\mathrm{F} capacitance whose plates are separated by 10 mm through air and each plate has area 4 cm24\ \mathrm{cm}^2…HardNumerical valueHas a figure
  3. 8 Apr 2024, Shift 2 · Q40A capacitor has air as dielectric medium and two conducting plates of area 12 cm212\ \mathrm{cm}^2 and they are 0.60.6 cm apart. When a slab of…MediumSingle correct
  4. 6 Apr 2023, Shift 1 · Q56A parallel plate capacitor with plate area A and plate separation d is filled with a dielectric material of dielectric constant K=4K=4. The…MediumNumerical valueHas a figure
  5. 27 Jul 2022, Shift 2 · Q56A 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…MediumNumerical value
  6. 28 Jul 2022, Shift 2 · Q9A slab of dielectric constant K has the same cross-sectional area as the plates of a parallel plate capacitor and thickness 34\frac{3}{4}…EasySingle correct
  7. 30 Jun 2022, Shift 1 · Q40Co\mathrm{C_o} is the capacitance of a parallel plate capacitor with air as a medium between the plates (as shown in Fig. 1). If half…EasySingle correctHas a figure
  8. 26 Aug 2021, Shift 2 · Q18A parallel-plate capacitor with plate area A has separation d between the plates. Two dielectric slabs of dielectric constant…MediumDiagram basedHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.