Question

1. if circuit current decreases, the magnetic field of an inductor ________.a expandsb contractsc stays the samed resists current

Explanation:

The magnetic field of an inductor is directly related to the current. When current decreases, the magnetic field strength (which depends on current \(I\) as \(B = \mu nI\) for a solenoid - like inductor, where \(\mu\) is permeability, \(n\) is number of turns per unit length) also decreases. A decrease in magnetic field strength means the magnetic field "contracts" (since it's getting weaker in extent). Option a is wrong as expansion would imply an increase in field (more current). Option c is wrong as current change affects field. Option d is about the inductor's property to resist change in current (inductive reactance concept) but not directly about the magnetic field's state when current decreases.

Answer:

B. contracts