# Electrical Engineering - Inductors - Discussion

### Discussion :: Inductors - General Questions (Q.No.21)

21.

The inductance of an iron-core coil decreases if

 [A]. the number of turns is decreased [B]. the iron core is removed [C]. the length of the coil decreases [D]. none of the above

Explanation:

No answer description available for this question.

 Kirthikumar Rao said: (Nov 23, 2011) Wkt LI=NQ L=inductance of the coil I=current N=no of turns of the coil Q=flux as inductance is directly proportional to no of turns

 Deep Sandholia said: (Nov 26, 2013) Flux is directly proportional to no.of turns.

 Dipak said: (Dec 2, 2014) L = N^2/R. L = INDUCTANCE. N = NUMBER OF TURNS. R = RELUCTANCE OF CORE.

 Eng. S.T.Arif said: (Apr 29, 2015) Inductance (Physical property of a coil) L = U.N2.l.A. U = Permeability of core, N2 = NxN (Number of turns). L = Length of coil. A = Cross sectional area of coil. So if to decrease L. You decrease (remove of iron core). Reduce N turns of coil. Reduce length of coil. The correct answer is not given in the question.

 Sandeshg said: (Jun 11, 2015) Answers A, B are correct. Air core has less permittivity as compared to iron core hence lesser the permittivity lesser the inductance of the coil.

 Svn said: (Jan 9, 2017) Right answer is both A and B.

 Deepak said: (Jan 19, 2018) Here, L=£N^2A/L.

 Haris said: (Jan 11, 2020) L = (permiability)*(no of turns)^2*Area/Length. L = u*N^2 * A/length.