Key relationship
P=ε₀(κ−1)E; σbound=P; Eisolated=E₀/κ.
Physics · Class 12
Dielectric polarization
Polarization slightly separates positive and negative bound charge. Compare a battery-connected capacitor, which holds voltage, with an isolated capacitor, which holds free charge.
Open the interactive experiment →Dielectric polarization
மின்காப்பானின் பிணை மின்னூட்டங்கள் சிறிது பிரிந்து துருவமாதல் உருவாக்கும். தனித்த தேக்கியில் புலம் குறையும்.
Key notes, relationships and model limits
Remember
Polarization slightly separates positive and negative bound charge. Compare a battery-connected capacitor, which holds voltage, with an isolated capacitor, which holds free charge.
Common trap
Check whether the capacitor is isolated or connected to a voltage source before deciding which quantity stays constant.
Model limits
Linear homogeneous dielectric fills the whole gap; no leakage, breakdown or fringing.
What you will learn
Use the controls and plotted relation to explain dielectric polarization.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
With κ=4 in an isolated capacitor, E and V fall to one quarter of their initial values.
Why this matters
The model connects dielectric polarization with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
When dielectric is added to an isolated charged capacitor, E becomes?
- κE₀ because the dielectric creates more free charge.
- E₀/κ, because free charge stays fixed.
- E₀ because the isolated voltage is fixed.
Read the explanation
E₀/κ, because free charge stays fixed.
Course connection: Class XII Chapter 2. Consult the roadmap for CBSE, NEET, JEE Main and Advanced scope.