Skip to content
Exercise · Q16

Q.Explain, in terms of magnetic permeability, why inserting a soft-iron core inside a current-carrying solenoid greatly increases the magnetic field it produces, compared to an identical air-core solenoid carrying the same current.

West Bengal WbchseTextbookSubjectiveImportance★★★★★
46% · 16/35 Questions
🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

For a solenoid of nn turns per unit length carrying current II, the field is B=μrμ0nIB=\mu_r\mu_0nI (Section 1.15), where μr\mu_r is the relative permeability of whatever fills the solenoid's interior. For an air core, μr≈1\mu_r\approx1, so B≈μ0nIB\approx\mu_0nI. For a soft-iron core, μr\mu_r is typically in the hundreds to low thousands (Section 1.14), so, for the IDENTICAL winding and current, the field is multiplied by that same large factor. …

Unlock everything free for 14 days

  • Full step-by-step solutions
  • Concept-first explanations
  • Methods, shortcuts & mistakes
  • PYQ mapping + timed mock tests

Full access for 14 days. No credit card required.