Electronics and Communication Engineering - Materials and Components - Discussion

Discussion Forum : Materials and Components - Section 1 (Q.No. 7)
7.
The core of a coil has a length of 10 cm. The self inductance is 8 mH. If the core length is doubled, all other quantities remaining the same, the self inductance will be
32 mH
16 mH
8 mH
4 mH
Answer: Option
Explanation:

Inductance is inversely proportional to the core length.

Discussion:
9 comments Page 1 of 1.

Priya said:   7 years ago
Please explain the answer in detail.

Eyob said:   8 years ago
L1=(m*N^2*A)/l then if l is doubled -->L2=(m*N^2*A)/2l = 1/2L1= 1/2 * 8 = 4.
(1)

Karthik said:   9 years ago
Good explanation. Thank you all.
(1)

M.A.salam said:   9 years ago
L = x/l.

Where l = 10.
Then x = L*l.
= 8 * 10 mH.

Again,
L = x/l ,where l = 20.

Then finally we got,

L = (8 * 10)/20.
= 4 mH.
(1)

Shinykiran said:   10 years ago
Inductance is inversely proportional to length.
(1)

KIRTI ARORA said:   1 decade ago
L= Permittivity*N^2*S/l.

L is proportional to 1/length of coil.

Shravya shamu said:   1 decade ago
If core value doubled then inductance value decrease to half.

Jitendra said:   1 decade ago
If all quantities are same then,
Let ((permeability)*(N^2)*A) = x.
Then L = x/l.

=> 8mH = x/10cm.
=> 0.5*8mH = (x/10)*0.5.
=> 4mH = x/20cm.

Then if the core length double then inductance is become half of pervious value.

Mehul Anghan said:   1 decade ago
L = ((permeability)*(N^2)*A)/l.

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