📚 Learning Guide
Electric Fields and Dielectrics
hard

In a parallel plate capacitor filled with a dielectric material, if the dielectric constant of the material is doubled, how will this affect the capacitance and the electric field between the plates when the charge remains constant?

Master this concept with our detailed explanation and step-by-step learning approach

Learning Path
Learning Path

Question & Answer
1
Understand Question
2
Review Options
3
Learn Explanation
4
Explore Topic

Choose the Best Answer

A

The capacitance will double, and the electric field will halve.

B

The capacitance will remain the same, and the electric field will double.

C

The capacitance will decrease, and the electric field will remain unchanged.

D

The capacitance will double, and the electric field will remain unchanged.

Understanding the Answer

Let's break down why this is correct

Answer

When the dielectric constant εr is doubled, the capacitance of the parallel‑plate capacitor also doubles because C = ε0 εr A/d. With the charge Q fixed, the voltage across the plates becomes V = Q/C, so the voltage drops to half its original value. Since the electric field between the plates is E = V/d, the field likewise halves. For example, if εr changes from 2 to 4, a 10 µF capacitor becomes 20 µF; with the same 5 µC of charge, the voltage falls from 0. 5 V to 0.

Detailed Explanation

Capacitance is directly proportional to the dielectric constant, so doubling it doubles the capacitance. Other options are incorrect because Some think the dielectric does not change capacitance, but it does; The misconception is that a larger dielectric constant reduces capacitance.

Key Concepts

Polarization in Dielectrics
Gauss's Law
Capacitance of Parallel Plate Capacitors
Topic

Electric Fields and Dielectrics

Difficulty

hard level question

Cognitive Level

understand

Ready to Master More Topics?

Join thousands of students using Seekh's interactive learning platform to excel in their studies with personalized practice and detailed explanations.