resistance of filament lamps

• Filament lamp


  A lamp that uses a very fine wire (filament) that gets extremely hot when an electric current passes through it, causing it to glow and emit light
• Current through a filament lamp

  Not directly proportional to the potential difference across it
• Filament lamp


  • Resistance increases at high temperature
  • Atoms in the filament vibrate more, causing electrons in the current to collide more with atoms, requiring more energy to push the current through
• As potential difference increases, the current no longer increases as much, indicating that resistance is increasing</b>
• Ohmic conductor


  A conductor where the current is directly proportional to the potential difference, meaning the resistance is constant
• A filament lamp is not an ohmic conductor