Question

• Discuss how the iron core changes the magnitude of induced voltage when it is inserted in a solenoid. What physical property of the iron core causes this change? Explain in the microscopic picture. What would happen if a copper core was used instead?

Answer 1

Iron core increases the magnitude of induced voltage in a solenoid.

High magnetic permeability of iron is responsible for the increase in induced voltage.

This happens because iron is a ferromagnetic substance and when it is placed inside a solenoid the magnetic domains inside the iron are aligned in the direction of the magnetic field, this increases the strength of the magnetic field inside the solenoid. This increases the magnetic flux through the solenoid , which in turn increases the induced emf.

When a copper rod is inserted inside the solenoid , the magnitude of induced emf through the solenoid decreases. This is because copper is a diamagnetic material hence it reduces the magnetic field inside the solenoid.