P4.2 Uses of Magnetism

• What is magnetism defined as?

  Force of attraction or repulsion
• How is magnetism used in electric motors?

  To produce rotational motion
• All magnets have two magnetic poles: a north pole and a south pole.


  True
• Generators use magnetism to convert mechanical energy into electrical energy.

  True
• Order the following magnetic separation techniques:

  1️⃣ Material mixture is fed into the system

  2️⃣ Magnetic components are attracted to a magnet

  3️⃣ Non-magnetic components are separated

  4️⃣ Magnetic components are removed
• Iron, nickel, and cobalt are examples of magnetic materials.
• The area around a magnet where magnetic forces can be detected is called the magnetic field.
• Magnetic levitation, or Maglev, is an application of magnetism to reduce friction.
• Match the magnetic property with its description:

  Magnetic field ↔️ Area around a magnet where magnetic forces are detected

  Magnetic poles ↔️ North and south ends of a magnet

  Magnetism ↔️ Force of attraction or repulsion between magnetic materials
• Magnetic field lines show the direction of the magnetic force.

  True
• Magnetic poles are always found in pairs: a north pole and a south pole.


  True
• Electric motors use the interaction between magnetic fields and current-carrying wires to produce rotational motion.
• In generators, mechanical energy is converted into electrical energy using electromagnetic induction.


  True
• What is the process called by which a moving magnetic field induces a current in a coil of wire?

  Electromagnetic induction
• Match the property of magnetism with its description:

  Poles ↔️ Magnets have a north and south pole

  Attraction ↔️ Opposite poles attract, like poles repel

  Magnetic field ↔️ The area around a magnet
• Electric motors use magnetism to convert electrical energy into mechanical energy.

  True
• What provides the rotation in a generator?

  External source
• What is one key advantage of Maglev trains compared to wheeled trains?

  Lower energy consumption
• Why are Maglev trains quieter than traditional trains?

  No physical contact
• Hard disks use magnetism to store binary data by manipulating magnetic polarity.


  True
• What does an area magnetized in one direction represent in a hard disk?

  1
• MRI is effective in visualizing soft tissues such as the brain, spine, and joints
• Which imaging method uses a strong magnetic field but no radiation?

  MRI
• Magnetic field lines show the direction of magnetic force.

  True
• In an electric motor, the current generates a magnetic field that interacts with the external magnetic field to produce rotation.


  True
• The commutator ensures continuous rotational motion in an electric motor by reversing the current direction every half rotation.


  True
• Steps in the operation of an electric motor

  1️⃣ Current flows through the wire coil in the armature

  2️⃣ The current generates a magnetic field around the coil

  3️⃣ This magnetic field interacts with the external magnetic field

  4️⃣ The force causes the armature to rotate

  5️⃣ The commutator reverses the current direction
• The commutator in an electric motor reverses the current direction every half rotation.


  True
• Faraday's law states that the induced current is proportional to the rate of change of magnetic flux.


  True
• What does the read-write head in a hard disk do?

  Magnetizes or demagnetizes areas
• Which magnetic material is strongly attracted to magnetic fields?

  Ferromagnetic
• The voice coil in a loudspeaker is attached to the cone which vibrates to produce sound.
• What is one medical application of magnetism mentioned in the text?

  MRI
• What happens when like poles of two magnets are brought near each other?

  They repel
• Where is the magnetic field strongest around a magnet?

  At the poles
• What happens when opposite poles of two magnets are brought near each other?

  They attract
• Order the steps in the operation of an electric motor:

  1️⃣ Current flows through the wire coil in the armature

  2️⃣ The current generates a magnetic field around the wire coil

  3️⃣ The coil's magnetic field interacts with the external magnetic field

  4️⃣ The armature rotates due to magnetic forces

  5️⃣ The commutator switches the current direction
• What is the role of the magnetic field in a generator?

  To induce current
• According to Faraday's law, the induced current is proportional to the rate of change of the magnetic flux.
• Magnetic field lines show the direction of the magnetic force.