Electronics and Communication Engineering - Materials and Components - Discussion

Discussion Forum : Materials and Components - Section 1 (Q.No. 16)
16.
A parallel plate capacitor has its length, width and separation doubled. It fringing effects are neglected, to keep the capacitance same, the dielectric constant must be
halved
kept the same
doubled
made 4 times
Answer: Option
Explanation:

. When dimensions are changed, A become four times and d becomes twice.

Since ∈0 is constant, ∈r must be halved to keep C constant.

Discussion:
7 comments Page 1 of 1.

Manju power said:   3 years ago
Area=L*W.

(L*2)*(W*2) =4.

Distance d=2.

DC will be constant...assume DC. = 1
C=eA/d
= 1*4/2= 2Farads.

Rakhul Rajumohan said:   5 years ago
@All.

It's Very simple.

Area wants to increase 4 and the distance between them becomes 2 then only we can maintain the dielectric constant same for any alternatives!

Ex:- area=4, distance = 2 then dc= 2 times, same as area =8, distance= 4 then dc= 2.

Likewise that,

Hope you understand clearly.

Banoth kalyan said:   7 years ago
Please Explain the answer in detail.

Deepak said:   8 years ago
Please explain in detail.

Priti said:   8 years ago
c=nA/d {where n is dielectric constant, A is an area of the plate which multiplied of length and width and d is separation area of the plate.

C1/C2=(k1*A1*d2)/(k2*A2*d1) {where A2=4A1 AND d2=2d1 and c1=c2
then k2=k1/2.
(1)

Mark D. said:   8 years ago
C=k*A/d,
C=k*(2L*2W)/2d,
C=(k/2)*(2L*2W)/2d.

Riya said:   10 years ago
Can anyone explain this answer in detail once again?

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