Question

how can the poles of solenoid interchanged???​

Answer 1

Hey..hi

The solenoid is simply a coil of wire with no directional component so it can simply be reversed in the circuit to generate the magnetic field in the opposite direction, or you can reverse the direction of the current traveling through the solenoid.

Answer 2

The solenoid itself is simply a coil of wire with no directional components (e.g. a diode), so it can simply be reversed in the circuit to generate the magnetic field in the opposite direction, or you can reverse the direction of the current traveling through the solenoid