12.1 Magnetic Fields and Forces

• What is a magnetic field defined as?

  Region with magnetic force
• What happens when like magnetic poles interact?

  Repulsion
• Water is a diamagnetic material.

  True
• What does the Lorentz force equation describe?

  Force on charged particle
• Arrange the steps to apply the right-hand rule for magnetic forces:

  1️⃣ Point your thumb in the direction of the velocity.

  2️⃣ Point your fingers in the direction of the magnetic field.

  3️⃣ Your palm shows the direction of the force on a positive charge.
• Ferromagnetic materials are strongly attracted to magnets
• Like magnetic poles repel each other.


  True
• Magnetic field lines emerge from North poles and enter South poles.


  True
• Magnetic field lines can intersect each other.

  False
• The Lorentz force is perpendicular to both velocity and the magnetic field.


  True
• What is the charge of a proton used in example calculations?

  +e
• What direction is the force on a positive charge moving eastward in a magnetic field pointing northward?

  Upward
• Permanent magnets are naturally magnetized materials with aligned magnetic domains
• Match the type of magnetic material with its definition:

  Ferromagnetic ↔️ Strongly attracted to magnets

  Paramagnetic ↔️ Weakly attracted to magnets

  Diamagnetic ↔️ Weakly repelled by magnets
• What direction do magnetic field lines emerge from?

  North pole
• In the Lorentz force equation, $q$ represents the charge of the particle
• What is an example of a permanent magnet?

  Compass needle
• What is an example of a paramagnetic material?

  Aluminum
• Magnetic field lines are closer together where the field is stronger
• The Lorentz force equation describes the force on a charged particle moving in a magnetic field
• The magnetic force on a charged particle is calculated using the Lorentz force equation
• The magnetic force on a proton moving in a magnetic field is calculated to be 20
• Electric currents produce magnetic fields.


  True
• Iron is an example of a ferromagnetic material
• Magnetic field lines form closed loops.


  True
• The Lorentz force is always perpendicular to both velocity and magnetic field.


  True
• Copper is an example of a diamagnetic material
• Diamagnetic materials are weakly repelled by magnets
• Which magnetic material retains magnetism once removed from a field?

  Ferromagnetic
• What type of loops do magnetic field lines always form?

  Closed loops
• What does $\vec{B}$ represent in the Lorentz force equation?


  Magnetic field vector
• Steps to apply the Lorentz force equation

  1️⃣ Identify the charge, velocity, and magnetic field

  2️⃣ Use the right-hand rule to determine the force direction

  3️⃣ Calculate the magnitude of the force
• Steps to use the right-hand rule for magnetic forces

  1️⃣ Point fingers along the velocity vector

  2️⃣ Curl fingers towards the magnetic field

  3️⃣ Thumb indicates the magnetic force direction