If both the number of turns and core length of an inductive coil are doubled, then its self inductance will be

This question was previously asked in
UKPSC JE Electrical 2013 Official Paper I (Held on 7 Nov 2015)
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  1. halved
  2. doubled
  3. quadrupled
  4. unaffected

Answer (Detailed Solution Below)

Option 2 : doubled
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UKPSC JE CE Full Test 1 (Paper I)
180 Qs. 360 Marks 180 Mins

Detailed Solution

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CONCEPT:

Self-Induction

  • Whenever the electric current passing through a coil changes, the magnetic flux linked with it will also change.
  • As a result of this, in accordance with Faraday’s laws of electromagnetic induction, an emf is induced in the coil which opposes the change that causes it.
  • This phenomenon is called ‘self-induction’ and the emf induced is called back emf, current so produced in the coil is called induced current.
  • Self-inductance of a solenoid is given by –

Where μo = Absolute permeability, N = Number of turns, l = length of the solenoid, and A = Area of the solenoid.

EXPLANATION:

Given - l2 = 2l1

N2 = 2 N1

Self-inductance of a solenoid is given by:

L2 = 2 L1​

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