Electromagnetic Induction and Alternating Current Cheat Sheet

Key Definitions

• Electromagnetic Induction: The process of generating electric current from a changing magnetic field. ✅

• Faraday's Law: The induced EMF in a circuit is proportional to the rate of change of magnetic flux. ✅

• Lenz's Law: The direction of induced current opposes the change in magnetic flux. ✅

• Alternating Current (AC): Electric current that reverses direction periodically. ✅

Important Concepts

Electromagnetic Induction

• Magnetic Flux: Φ = B A cos(θ)

• B: Magnetic field strength

• A: Area

• θ: Angle between B and the normal to A

• Induced EMF:

• EMF = -dΦ/dt (Faraday's Law) ✅

Alternating Current

• AC Voltage: V(t) = V₀ * sin(ωt + φ)

• V₀: Peak voltage

• ω: Angular frequency

• φ: Phase angle

• RMS Voltage: V_rms = V₀ / √2 ✅

• RMS Current: I_rms = I₀ / √2 ✅

Key Formulas

• Faraday's Law: EMF = -dΦ/dt ✅

• Magnetic Flux: Φ = B A cos(θ) ✅

• AC Voltage: V(t) = V₀ * sin(ωt + φ) ✅

• RMS Voltage: V_rms = V₀ / √2 ✅

• RMS Current: I_rms = I₀ / √2 ✅

Common Mistakes to Avoid

Common Mistake: Confusing the direction of induced current with the direction of the magnetic field.

Memory Tricks

Tip: "FLEM" — Faraday, Lenz, EMF, Magnetic flux — key concepts to remember in electromagnetic induction.

Key Diagrams

Magnetic Flux and Induced EMF
      B
      ↑
      |   
      |  +----+
      |  |    | A
      |  |    |
      |  +----+
      |
      -----> Induced Current

AC Voltage Waveform
   |       /\
   |      /  \
   |     /    \
   |    /      \
   |___/        \______
   |   |        |      |
   |   |        |      |
   |___|________|______|_____
       0   T/2   T