How can the electric current in the coil be changed?

You can change the current in the inductor by changing the number of turns; if you insert a metal (or any other magnetic material) core, then the inductance will increase, and since the inductance is inversely proportional to the change in current, the current will decrease; change the amperage in the entire circuit.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.