7.1.2 Permanent & Induced Magnets

• What is the definition of permanent magnets?

  Permanent magnets are materials that produce their own magnetic field and retain their magnetic properties over time without an external power source.
• What are the magnetic poles of permanent magnets?

  Permanent magnets have north and south poles, with magnetic field lines emerging from the north pole and entering the south pole.
• Why are permanent magnets useful in various applications?

  They maintain their magnetic properties consistently.
• What are common materials used to make permanent magnets?

  Common materials include ferromagnetic materials such as iron, cobalt, and nickel.
• How do ferromagnetic materials become permanent magnets?

  They have magnetic domains that align in the presence of a magnetic field, and this alignment persists.
• What is an example of a permanent magnet?

  Bar magnets are often used in classrooms to demonstrate magnetic principles.
• What is a common use of permanent magnets?

  Permanent magnets are used in compasses to help in navigation.
• What defines induced magnets?

  Induced magnets are materials that become magnetic only when placed within a magnetic field.
• What happens to induced magnets when the external magnetic field is removed?

  They lose their magnetism and return to their non-magnetic state.
• What materials are commonly used as induced magnets?

  Soft ferromagnetic materials, such as soft iron, are commonly used as induced magnets.
• What is an example of an induced magnet?


  Iron nails become temporarily magnetized when placed near a magnet.
• How do electromagnets utilize induced magnetism?

  The core material, often soft iron, becomes magnetized only while the current is flowing through the coil.
• What is a common use of induced magnets?

  Induced magnets are used in electromagnets for applications like electric bells and relays.
• What is the difference in persistence of magnetism between permanent and induced magnets?

  Permanent magnets retain their magnetism indefinitely, while induced magnets only exhibit magnetism when exposed to an external magnetic field.
• What types of materials are used to make permanent magnets?

  Permanent magnets are made from materials that can retain magnetic properties over time.
• What types of materials are used to make induced magnets?

  Induced magnets are made from materials that can easily become magnetized but do not retain magnetism after the external field is removed.
• In what applications are permanent magnets typically used?

  Permanent magnets are used where a constant magnetic field is needed.
• In what applications are induced magnets typically used?

  Induced magnets are used where temporary magnetism is required, often in electrical devices and machinery.
• What are the key differences between permanent and induced magnets?

  • **Persistence of Magnetism:**
  • Permanent Magnets: Retain magnetism indefinitely.
  • Induced Magnets: Exhibit magnetism only in an external magnetic field.
  • **Material Types:**
  • Permanent Magnets: Made from materials that retain magnetic properties.
  • Induced Magnets: Made from materials that easily become magnetized but lose magnetism after the field is removed.
  • Applications:
  • Permanent Magnets: Used for constant magnetic fields.
  • Induced Magnets: Used for temporary magnetism in devices.
• What are some examples and experiments related to permanent and induced magnets?

  • **Permanent Magnet Example:**
  • Bar Magnet Experiment: Demonstrates attraction and repulsion of magnetic poles and maps magnetic field lines using iron filings.
  • **Induced Magnet Example:**
  • Induced Magnet Experiment: Soft iron nail becomes magnetized near a strong magnet and loses magnetism when the magnet is removed.
• What is the summary of permanent and induced magnets?

  • **Permanent Magnets:**
  • Retain magnetic properties without an external field.
  • Common materials: iron, cobalt, nickel.
  • Used in everyday applications (e.g., compasses, electric motors).
  • **Induced Magnets:**
  • Exhibit magnetism only in an external magnetic field.
  • Common material: soft iron.
  • Used in devices requiring temporary magnetism (e.g., electromagnets, transformers).