Electromag Induction

• What induces voltage in a conductor or coil?

  Movement through a magnetic field
• What does Faraday's Law state about induced voltage?

  It is proportional to the rate of change
• What factors affect induced voltage?

  1. Strength of Magnetic Field
  2. Speed of Motion
  3. Number of Turns in Coil
  4. Angle of Movement
• How does the strength of the magnetic field affect induced voltage?

  Stronger fields induce more voltage
• What happens to induced voltage with increased speed of motion?

  It induces more voltage
• How does the number of turns in a coil affect induced voltage?

  More turns result in higher voltage
• When is maximum voltage induced in relation to movement angle?

  When motion is perpendicular to the field
• What principle generates electricity via rotation?

  Coil rotates within a magnetic field
• What type of current do alternators generate?

  Alternating current (AC)
• How does the current behave in an alternator?

  It changes direction every half turn
• What do dynamos generate?

  Direct current (DC)
• How do dynamos ensure current flows in one direction?

  Using a split-ring commutator
• What is the structure of a transformer?

  • Core: Made of soft iron
  • Coils:

  1. Primary Coil: Input voltage source
  2. Secondary Coil: Output voltage
• What is the function of transformers?

  Change voltage of alternating current (AC)
• What do step-up transformers do?

  Increase voltage from primary to secondary
• Why are step-up transformers used in power stations?

  To transmit electricity efficiently over distances
• What do step-down transformers do?

  Decrease voltage from primary to secondary
• Why are step-down transformers used in homes?

  To provide safe voltage levels for appliances
• What is the transformer equation relationship?

  • Voltage across primary coil: $V_p$
  • Voltage across secondary coil: $V_s$
  • Number of turns in primary coil: $N_p$
  • Number of turns in secondary coil: $N_s$
• What happens with a higher number of turns in the secondary coil?

  Results in a higher output voltage
• What happens with a lower number of turns in the secondary coil?

  Results in a lower output voltage
• What is the power relationship in transformers?

  • Power in primary coil: $P_p$
  • Power in secondary coil: $P_s$
  • Current in primary coil: $I_p$
  • Current in secondary coil: $I_s$
• What is the efficiency of an ideal transformer?

  100% efficient
• What are the energy losses in real transformers?

  1. Resistance in Coils
  2. Eddy Currents
  3. Magnetic Leakage
• How can energy loss be minimized in transformers?

  Use low-resistance wires
• What is the purpose of laminating the iron core?

  To reduce eddy currents
• How can coils be designed to minimize energy loss?

  To maximize magnetic linkage
• What are the key points about induced voltage?

  • Induced by motion or changing magnetic fields
  • Depends on speed, field strength, and coil turns
• What are the key points about electricity generation?

  • Alternators (AC) and dynamos (DC)
  • Use rotation within magnetic fields
• What are the key points about transformers?

  • Change AC voltage using electromagnetic induction
  • Consist of primary and secondary coils
• What are the key points about step-up transformers?

  • Increase voltage
  • Used for efficient power transmission
• What are the key points about step-down transformers?

  • Decrease voltage
  • Used for safe domestic and industrial use
• What is the transformer equation implication?

  • Voltage ratio equals coil turn ratio