🔍 Key Concepts

• Magnetic materials in generators and motors and how they respond to changing magnetic fields • Difference between electrical losses (current/voltage related) vs magnetic core losses • What happens inside an iron core when the magnetic polarity is reversed many times per second

💭 Think About

• Which of the choices clearly involves the behavior of the magnetic core itself, rather than brushes, current flow, or field strength? • Think about AC generators: as the magnetic field reverses each cycle, what extra energy is required to repeatedly magnetize and demagnetize the iron? • Which option would naturally produce heat in the iron or steel parts of the machine, even if the windings and brushes were perfect?

✅ Before You Answer

• Identify which answers relate to mechanical/contact issues (like brushes) and which relate to magnetic behavior in the core • Ask: hysteresis is a lag in magnetization when a magnetic field changes. Which choice best matches that idea? • Focus on the option that would cause core losses and heating every time the magnetic field changes direction.