A parallel plate capacitor on a 100 V battery
"A parallel plate capacitor on a 100 V battery" is a free, interactive Class 12 Physics simulation for NEET and JEE, built on the lesson "Effect of dielectric on capacitance" in Electrostatic Potential and Capacitance. Change the gap between them and what fills it. Watch the charge on the plates, the field lines in the gap and the capacitance. C = Kε₀A/d depends only on the plates and what fills the gap. With the battery connected V is fixed, so a dielectric or a smaller gap pulls more charge onto the plates, Q = CV. JEE Main asked 48 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
From the lesson Effect of dielectric on capacitance in Electrostatic Potential and Capacitance. Change the values and watch what happens.
In JEE Main
42 shifts analysed
48 questions from Electrostatic Potential and Capacitance across the 42 JEE Main shifts Lumi has analysed (2017–2026).
The idea behind it
NCERT §2.13
- With vacuum between the plates, E₀ = σ/ε₀, V₀ = E₀d and C₀ = ε₀A/d.
- A dielectric filling the gap is polarised; its bound surface charges ±σₚ cut the effective charge density to σ − σₚ, so E = (σ − σₚ)/ε₀.
- For a linear dielectric σ − σₚ = σ/K, where K > 1 is the dielectric constant. The field and V both fall by the factor K for the same charge.
- Hence C = Kε₀A/d = KC₀. The dielectric constant is the factor by which capacitance grows when the dielectric fills the space fully.
- Permittivity of the medium ε = ε₀K; K = ε/ε₀ is dimensionless. For vacuum K = 1.
- C = KC₀ holds for a capacitor of any shape, so it can serve as the definition of K.
- Slab partly filling the gap: a slab of constant K and thickness 3d/4 (full plate area) makes V = E₀d(K + 3)/(4K) for the same charge, so C = 4KC₀/(K + 3).
Questions
3 answers
- What does the "A parallel plate capacitor on a 100 V battery" simulation show?
- Change the gap between them and what fills it. Watch the charge on the plates, the field lines in the gap and the capacitance.
- Does JEE Main ask questions from Electrostatic Potential and Capacitance?
- Yes. JEE Main asked 48 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
- Is this simulation free?
- Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Effect of dielectric on capacitance" in Electrostatic Potential and Capacitance (Class 12 Physics).
Embed this simulation
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