resistance

• The unit of measurement for resistance is ohms (Ω)
• Ohm's law states that voltage = current x resistance
• potential difference(v) = current(i) x resistance(r)
• delocalised electrons flow and collide with positive ions in a current creating resistance
• in diodes, current only flows in one direction so resistance is extremely high in the other direction
• ohmic conductors are at a constant temp so current is directly proportional to pd
• in a filament bulb, as the current increases, the filament bulb heats up more and resistance increases
• adding components to a series circuit increases resistance
• in a filament bulb, the electric charge flowing through it transfers energy to its thermal energy store