electromagnetic introduction

• What factors determine the size of the induced potential difference?

  Speed, number of turns, size of coils, strength of magnetic field
• How does increasing the speed of movement affect the induced potential difference?

  It increases the rate of cutting magnetic field lines
• What happens to the induced potential difference if the number of turns on the coils is increased?

  It increases the potential difference induced
• Why does increasing the size of the coils increase the induced potential difference?

  More wire cuts through the magnetic field lines
• How does the strength of the magnetic field affect the induced potential difference?

  Increasing strength increases the potential difference induced
• What determines the direction of the induced potential difference?

  The orientation of the poles of the magnet
• What does the induced potential difference always do in relation to the change that produces it?

  It always opposes the change that produces it
• What happens when a magnet is pushed north end first into a coil of wire?

  The end of the coil closest becomes a north pole
• What is the effect of pulling a magnet away from a coil of wire?

  The end of the coil closest becomes a south pole
• What is the relationship between the direction of the induced current and the movement of the magnet?

  The induced current reverses with the magnet's direction
• What is the structure of a basic transformer?

  A primary coil, a secondary coil, and an iron core
• Why is iron used in transformers?

  Because it is easily magnetised
• How does an alternating current affect the primary coil in a transformer?

  It produces a changing magnetic field around the coil
• What happens to the potential difference in the secondary coil of a transformer?

  It induces an alternating potential difference
• What is the role of transformers in the national grid?

  To change the size of alternating voltage
• What is a step-up transformer?

  A transformer with more turns on the secondary coil
• What is a step-down transformer?

  A transformer with fewer turns on the secondary coil
• Why is electricity transmitted at high voltages?

  To reduce current and minimize energy loss
• How does the equation $P =$$IV$ relate to power transmission?


  Higher voltage allows lower current for same power
• What is the ideal transformer equation for efficiency?

  $Vp \times Ip =$$Vs \times Is$
• In a transformer, if $Vp =$$115 \text{ V}$ and $Vs =$$230 \text{ V}$, what is the relationship between currents?


  $Ip =$$10 \text{ A}$
• What are the roles of transformers in electricity transmission?

  • Increase potential difference for transmission
  • Lower high voltage for domestic use
  • Used in adapters for electronic devices
• What are the key differences between step-up and step-down transformers?

  Step-up transformer:

  • More turns on secondary coil
  • Increases potential difference

  
  

  Step-down transformer:

  • Fewer turns on secondary coil
  • Decreases potential difference
• What are the key points to remember when discussing induced potential difference?

  • Add more turns to the coil
  • Use a stronger magnet
  • Avoid confusing size with strength
• What is the significance of the ideal transformer equation?

  • Indicates conservation of energy
  • Relates input and output power
  • Essential for calculating current and voltage relationships
• What happens to the voltmeter when a magnet is stationary in the coil?

  • No deflection occurs
  • No relative movement means no induced potential difference
• What happens to the voltmeter when a magnet is pulled out of the coil?

  • The needle deflects to the left
  • Indicates induced potential difference due to movement
• What happens to the voltmeter when a magnet is pushed into the coil?

  • The needle deflects to the right
  • Indicates induced potential difference due to movement
• What is the relationship between power, voltage, and current in transformers?

  • Power is conserved: $P =$$VI$
  • Input power equals output power in ideal transformers
• What is the effect of high voltage transmission on energy loss?

  • Reduces current
  • Minimizes energy loss in wires
• What is the significance of the generator effect in EM induction?

  • Induces potential difference in coils
  • Opposes changes in magnetic field
• What is the role of the iron core in a transformer?

  • Enhances magnetic field strength
  • Facilitates efficient energy transfer
• What is the relationship between the direction of induced current and the movement of the magnet?

  • Induced current direction reverses with magnet movement
  • Follows Lenz's law
• What is the importance of checking current and potential difference in transformer problems?

  • Ensures correct application of formulas
  • Avoids errors in calculations
• What is the effect of increasing the number of turns on the coil in EM induction?

  • Increases induced potential difference
  • More coils cut magnetic field lines
• What is the effect of increasing the area of the coils in EM induction?

  • Increases induced potential difference
  • More wire cuts through magnetic field lines