Case: Read the passage and answer the question.
The number of magnetic field lines crossing a surface is called the magnetic flux. An electric current can be induced in a coil by a flux change produced by another coil in its vicinity or by a flux change produced by the same coil. The former is called mutual induction and the latter is called self-induction.
For a coil, \( N\Phi_B\propto I \). What is the constant of proportionality called?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Inductance
NCERT (2026-27):
Inductance – “For a closely wound coil of N turns, the same magnetic flux is linked with all the turns. When the flux ΦB through the coil changes, each turn contributes to the induced emf. Therefore, a term called flux linkage is used which is equal to NΦB for a closely wound coil and in such a case
\( N\Phi_B\propto I \)
The constant of proportionality, in this relation, is called inductance.”