ExamBro
ExamBro
MHT CET · Physics · Electromagnetic Induction

Self-induction of a solenoid cannot be increased by

  1. A decreasing its length
  2. B increasing its area of cross-section
  3. C increasing the current through it
  4. D increasing the number of turns in it
Verified Solution

Answer & Solution

Correct Answer

(C) increasing the current through it

Step-by-step Solution

Detailed explanation

For a solinoid magnetic field at the center is:
\(B=\mu_0\left(\frac{N}{l}\right) I\),
Total magnetic self flux is:
\(\phi=B A N=\mu_0\left(\frac{N}{l}\right) I A N\)
According to the definition of magnetic flux and coefficient of self induction:
\(\phi=L I\)
On comparing the above two expressions, the self-induction of a long solenoid is given by
\(L=\frac{\mu_0 N^2}{L}\)
where, \(N=\) number of truns, \(L=\) Length and \(A=\) cross - sectional area.
Therefore, the self-induction of a long solenoid does not depend upon the current flowing through it.