Resistance

Factors affecting resistance:

• Length

  • The electrons have to travel a longer length and thus encounter more resistance.

• Cross-sectional area

  • More electrons can flow per unit time, increasing the current and therefore decreasing the resistance.

• Material

  • Better conductor = less resistance

• Current Voltage Character of an Ohmic Resistor and a Filament Lamp:

• Ohm's law states that voltage across a resistor is directly proportional to the current through it. This is only true if the temperature of the resistor or lamp remains constant