Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
A parallel plate air capacitor has a capacitance C. When it is half-filled with a dielectric constant 5, the percentage increase in the capacitance will be
PhysicsElectrostaticsNEET
Options:
  • A 400 %
  • B 66.6 %
  • C 33.3 %
  • D 200 %
Solution:
2082 Upvotes Verified Answer
The correct answer is: 66.6 %
Initial capacitance

                   C=ε0Ad



When it is half filled by a dielectric of dielectric constant K, then

       C 1 = K ε 0 A d / 2 = 2 K ε 0 A d

and  C 2 = ε 0 A d / 2 = 2 ε 0 A d

                     1C''=1C1+1C2

                             =d2ε0A1K+1=d2ε0A15+1

                             =610 dε0A

                    C''=5ε0A3d

Hence, increase in capacitance

                             = 53ε0Ad-ε0Adε0Ad=53-1=23=66.6% 

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.