Machine-translated by Google. Questions are authored in English.
Top

Discussion

The self-inductance of an air core solenoid is L. If the number of turns in the solenoid is doubled, keeping all other factors constant, then its self-inductance will be

  • A.\(L\)
  • B.\(\frac{L}{2}\)
  • C.\(2L\)
  • D.\(4L\)
  • E.\(8L\)

Answer: D

The self-inductance becomes \(4L\).

For a solenoid, \(L = \frac{\mu_{0}N^{2}A}{l}\). The field inside is proportional to \(N\), and the flux links all \(N\) turns, so \(L \propto N^{2}\). Doubling \(N\) with the same length and area multiplies \(L\) by \(2^{2} = 4\).

\(2L\) assumes \(L \propto N\), counting either the field or the linkage but not both. \(8L\) would be a cube law.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.