7.1.2 Electromagnetism

• What is electromagnetism?

  Interaction between electricity and magnetism
• When an electric current flows through a wire, it creates a magnetic field
• A changing magnetic field can induce an electric current in a conductor
• What is the name of the law that mathematically describes electromagnetic induction?

  Faraday's Law of Induction
• In Faraday's Law, the electromotive force $\mathcal{E}$ is equal to $- N \frac{d\Phi}{dt}$, where $N$ is the number of turns
• What does $\frac{d\Phi}{dt}$ represent in Faraday's Law?


  Rate of change of magnetic flux
• Match the features with the correct type of magnet:

  Permanent Magnets ↔️ Fixed strength

  Electromagnets ↔️ Controllable by current
• Electromagnets require a power source
• What is the power source for permanent magnets?

  None
• Steps to create an electromagnet

  1️⃣ Wrap a coil of wire around a magnetic core

  2️⃣ Pass an electric current through the coil

  3️⃣ Generate a magnetic field
• Which factor directly affects the strength of an electromagnet's magnetic field?

  Amount of current
• The strength of an electromagnet depends on the number of turns
• What type of core material is commonly used in electromagnets?

  Iron
• What is a key difference between permanent magnets and electromagnets in terms of their magnetic field strength?

  Fixed vs adjustable
• Electromagnets require a power source to function, while permanent magnets do not.
• Permanent magnets are commonly used in motors, generators, and transformers.

  False
• What is electromagnetism defined as?

  Interaction between electricity and magnetism
• In electromagnetism, changing magnetic fields induce electric currents.
• The strength of the magnetic field around a wire increases as the distance from the wire increases.

  False
• What is Faraday's Law of Induction used to calculate?

  Electromotive force
• In Faraday's Law of Induction, $N$ represents the number of turns in the coil.
• The strength of the magnetic field around a wire is directly proportional to the distance from the wire.

  False
• What does $\mathcal{E}$ represent in Faraday's Law of Induction?


  Electromotive force
• Electric currents generate magnetic fields in electromagnetism.
• The rate of change of magnetic flux is measured in webers per second.
• What is the unit of electromotive force ($\mathcal{E}$) in Faraday's Law of Induction?


  Volts
• Electromagnetic induction occurs when a constant magnetic field induces an electric current.

  False
• Order the key features of permanent magnets and electromagnets based on their differences:

  1️⃣ Magnetic field: Constant vs Controllable by current

  2️⃣ Strength: Fixed vs Adjustable

  3️⃣ Power source: None vs Requires electricity
• Electromagnetism is the interaction between electricity and magnetism
• Electric currents generate magnetic fields.
• What is the relationship between the strength of a magnetic field around a wire and the current through it?

  Proportional
• The strength of the magnetic field around a wire is inversely proportional to the distance
• Electromagnetic induction occurs when a changing magnetic field induces an electric current.
• What is the formula for Faraday's Law of Induction?

  $\mathcal{E} =$$- N \frac{d\Phi}{dt}$
• In Faraday's Law, $\frac{d\Phi}{dt}$ represents the rate of change of magnetic flux
• The number of turns in a coil affects the induced electromotive force.
• What is a key difference between permanent magnets and electromagnets in terms of their magnetic field?

  Constant vs. controllable
• The magnetic field of a permanent magnet is constant, while the magnetic field of an electromagnet can be controlled by the current
• The strength of a permanent magnet's magnetic field can be adjusted.

  False
• What is a requirement for electromagnets that is not needed for permanent magnets?

  Electricity